<?xml version="1.0" encoding="us-ascii"?>
<!--Generated by Broadridge PROfile 25.1.1.5279 Broadridge-->
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:t1="http://xbrl.org/2005/xbrldt">
  <link:roleRef roleURI="http://telixpharma.com/role/EventsOccurringAfterReportingPeriodAcquisitionOfAssetsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#EventsOccurringAfterReportingPeriodAcquisitionOfAssetsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/EventsOccurringAfterReportingPeriodAcquisitionOfRlsUsaIncDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#EventsOccurringAfterReportingPeriodAcquisitionOfRlsUsaIncDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/RemunerationOfAuditorDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#RemunerationOfAuditorDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/RelatedPartyTransactionsInterestsInOtherEntitiesDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#RelatedPartyTransactionsInterestsInOtherEntitiesDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/RelatedPartyTransactionsTransactionsWithOtherRelatedPartiesDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#RelatedPartyTransactionsTransactionsWithOtherRelatedPartiesDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/RelatedPartyTransactionsKeyManagementPersonnelCompensationDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#RelatedPartyTransactionsKeyManagementPersonnelCompensationDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/CommitmentsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#CommitmentsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/ContingentLiabilitiesDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#ContingentLiabilitiesDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/FinancialRiskManagementFairValueDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#FinancialRiskManagementFairValueDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/FinancialRiskManagementRemainingContractualMaturitiesDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#FinancialRiskManagementRemainingContractualMaturitiesDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/FinancialRiskManagementCreditRiskDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#FinancialRiskManagementCreditRiskDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/FinancialRiskManagementForeignCurrencyRiskDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#FinancialRiskManagementForeignCurrencyRiskDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/CashFlowInformationDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#CashFlowInformationDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/SharebasedPaymentsFairValueOfGrantDateInputsForOptionsGrantedDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#SharebasedPaymentsFairValueOfGrantDateInputsForOptionsGrantedDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/SharebasedPaymentsNumberOfOptionsIssuedUnderEquityIncentivePlanOutstandingDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#SharebasedPaymentsNumberOfOptionsIssuedUnderEquityIncentivePlanOutstandingDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/SharebasedPaymentsShareBasedCompensationExpenseDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#SharebasedPaymentsShareBasedCompensationExpenseDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/SharebasedPaymentsNumberAndWeightedAverageExercisePriceOfStockOptionsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#SharebasedPaymentsNumberAndWeightedAverageExercisePriceOfStockOptionsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/SharebasedPaymentsEquityIncentivePlanAndOptionsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#SharebasedPaymentsEquityIncentivePlanAndOptionsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/EquityFinancialAssetsAtFvociReserveDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#EquityFinancialAssetsAtFvociReserveDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/EquitySharebasedPaymentsReserveDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#EquitySharebasedPaymentsReserveDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/EquityOtherReservesDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#EquityOtherReservesDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/EquityShareCapitalReserveDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#EquityShareCapitalReserveDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/EquityShareCapitalDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#EquityShareCapitalDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/EmployeeBenefitObligationsDetailsCalc2" xlink:type="simple" xlink:href="tlx-20241231.xsd#EmployeeBenefitObligationsDetailsCalc2" />
  <link:roleRef roleURI="http://telixpharma.com/role/EmployeeBenefitObligationsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#EmployeeBenefitObligationsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/ContingentConsiderationArtmsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#ContingentConsiderationArtmsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/ContingentConsiderationIsoTherapeuticsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#ContingentConsiderationIsoTherapeuticsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/ContingentConsiderationTelixInnovationsTelixSwitzerlandAndTelixOptimalTracersDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#ContingentConsiderationTelixInnovationsTelixSwitzerlandAndTelixOptimalTracersDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/ContingentConsiderationContingentConsiderationDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#ContingentConsiderationContingentConsiderationDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/ProvisionsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#ProvisionsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/LeaseLiabilitiesInterestExpenseRelatingToLeasesDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#LeaseLiabilitiesInterestExpenseRelatingToLeasesDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/LeaseLiabilitiesLeaseLiabilitiesDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#LeaseLiabilitiesLeaseLiabilitiesDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/LeaseLiabilitiesLeasePaymentsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#LeaseLiabilitiesLeasePaymentsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/ContractLiabilitiesWalloonRegionNonreimbursableGrantDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#ContractLiabilitiesWalloonRegionNonreimbursableGrantDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/ContractLiabilitiesGrandPharmaStrategicPartnershipDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#ContractLiabilitiesGrandPharmaStrategicPartnershipDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/ContractLiabilitiesLiabilitiesRelatedToContractsWithCustomersDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#ContractLiabilitiesLiabilitiesRelatedToContractsWithCustomersDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/BorrowingsReconciliationOfLiabilitiesArisingFromFinancingActivitiesDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#BorrowingsReconciliationOfLiabilitiesArisingFromFinancingActivitiesDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/BorrowingsConvertibleBondsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#BorrowingsConvertibleBondsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/BorrowingsWorkingCapitalFacilityDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#BorrowingsWorkingCapitalFacilityDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/BorrowingsBankLoansDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#BorrowingsBankLoansDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/BorrowingsLendersDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#BorrowingsLendersDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/BorrowingsBorrowingsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#BorrowingsBorrowingsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/TradeAndOtherPayablesDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#TradeAndOtherPayablesDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/AcquisitionsQsamBiosciencesIncDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#AcquisitionsQsamBiosciencesIncDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/AcquisitionsArtmsIncDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#AcquisitionsArtmsIncDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/AcquisitionsIsotherapeuticsGroupLlcDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#AcquisitionsIsotherapeuticsGroupLlcDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/IntangibleAssetsImpairmentDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#IntangibleAssetsImpairmentDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/IntangibleAssetsCashGeneratingUnitsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#IntangibleAssetsCashGeneratingUnitsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/IntangibleAssetsNetBookAmountDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#IntangibleAssetsNetBookAmountDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/RightofuseAssetsDepreciationChargeOnRightofuseAssetsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#RightofuseAssetsDepreciationChargeOnRightofuseAssetsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/RightofuseAssetsRightofuseAssetsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#RightofuseAssetsRightofuseAssetsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/PropertyPlantAndEquipmentDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#PropertyPlantAndEquipmentDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/DeferredTaxAssetsAndLiabilitiesUnrecognizedTaxLossesDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#DeferredTaxAssetsAndLiabilitiesUnrecognizedTaxLossesDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/DeferredTaxAssetsAndLiabilitiesUnrecognizedDeferredTaxAssetsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#DeferredTaxAssetsAndLiabilitiesUnrecognizedDeferredTaxAssetsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/DeferredTaxAssetsAndLiabilitiesDeferredTaxAssetsAndLiabilitiesDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#DeferredTaxAssetsAndLiabilitiesDeferredTaxAssetsAndLiabilitiesDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/FinancialAssetsAdditionsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#FinancialAssetsAdditionsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/FinancialAssetsSummaryDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#FinancialAssetsSummaryDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/OtherCurrentAssetsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#OtherCurrentAssetsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/InventoriesDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#InventoriesDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/TradeAndOtherReceivablesDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#TradeAndOtherReceivablesDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/EarningsPerShareDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#EarningsPerShareDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/IncomeTaxExpenseBenefitNumericalReconciliationOfPrimaFacieTaxPayableToIncomeTaxExpenseBenefitDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#IncomeTaxExpenseBenefitNumericalReconciliationOfPrimaFacieTaxPayableToIncomeTaxExpenseBenefitDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/IncomeTaxExpenseBenefitSummaryDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#IncomeTaxExpenseBenefitSummaryDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/FinanceCostsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#FinanceCostsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/OtherGainsLossesNetDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#OtherGainsLossesNetDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/DepreciationAndAmortizationDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#DepreciationAndAmortizationDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/EmploymentCostsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#EmploymentCostsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/GeneralAndAdministrationCostsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#GeneralAndAdministrationCostsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/ResearchAndDevelopmentCostsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#ResearchAndDevelopmentCostsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/RevenueFromContractsWithCustomersDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#RevenueFromContractsWithCustomersDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/SegmentReportingGeographicalInformationDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#SegmentReportingGeographicalInformationDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/SegmentReportingOperatingSegmentAssetsAndLiabilitiesDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#SegmentReportingOperatingSegmentAssetsAndLiabilitiesDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/SegmentReportingReconciliationOfSegmentAdjustedEbitdaAndGroupAdjustedEbitaDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#SegmentReportingReconciliationOfSegmentAdjustedEbitdaAndGroupAdjustedEbitaDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/SegmentReportingSegmentPerformanceDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#SegmentReportingSegmentPerformanceDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/MaterialAccountingPolicyInformationRevenueDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#MaterialAccountingPolicyInformationRevenueDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/MaterialAccountingPolicyInformationTradeAndOtherPayablesDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#MaterialAccountingPolicyInformationTradeAndOtherPayablesDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/MaterialAccountingPolicyInformationIntangibleAssetsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#MaterialAccountingPolicyInformationIntangibleAssetsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/MaterialAccountingPolicyInformationPropertyPlantAndEquipmentDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#MaterialAccountingPolicyInformationPropertyPlantAndEquipmentDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/MaterialAccountingPolicyInformationBusinessCombinationsDetails" xlink:type="simple" xlink:href="tlx-20241231.xsd#MaterialAccountingPolicyInformationBusinessCombinationsDetails" />
  <link:roleRef roleURI="http://telixpharma.com/role/EventsOccurringAfterReportingPeriodTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#EventsOccurringAfterReportingPeriodTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/RemunerationOfAuditorTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#RemunerationOfAuditorTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/RelatedPartyTransactionsTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#RelatedPartyTransactionsTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/CommitmentsTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#CommitmentsTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/FinancialRiskManagementTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#FinancialRiskManagementTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/CashFlowInformationTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#CashFlowInformationTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/SharebasedPaymentsTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#SharebasedPaymentsTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/EquityTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#EquityTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/EmployeeBenefitObligationsTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#EmployeeBenefitObligationsTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/ContingentConsiderationTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#ContingentConsiderationTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/ProvisionsTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#ProvisionsTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/LeaseLiabilitiesTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#LeaseLiabilitiesTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/ContractLiabilitiesTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#ContractLiabilitiesTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/BorrowingsTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#BorrowingsTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/TradeAndOtherPayablesTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#TradeAndOtherPayablesTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/AcquisitionsTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#AcquisitionsTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/IntangibleAssetsTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#IntangibleAssetsTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/RightofuseAssetsTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#RightofuseAssetsTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/PropertyPlantAndEquipmentTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#PropertyPlantAndEquipmentTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/DeferredTaxAssetsAndLiabilitiesTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#DeferredTaxAssetsAndLiabilitiesTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/FinancialAssetsTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#FinancialAssetsTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/OtherCurrentAssetsTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#OtherCurrentAssetsTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/InventoriesTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#InventoriesTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/TradeAndOtherReceivablesTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#TradeAndOtherReceivablesTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/EarningsPerShareTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#EarningsPerShareTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/IncomeTaxExpenseBenefitTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#IncomeTaxExpenseBenefitTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/FinanceCostsTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#FinanceCostsTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/OtherGainsLossesNetTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#OtherGainsLossesNetTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/DepreciationAndAmortizationTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#DepreciationAndAmortizationTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/EmploymentCostsTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#EmploymentCostsTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/GeneralAndAdministrationCostsTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#GeneralAndAdministrationCostsTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/ResearchAndDevelopmentCostsTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#ResearchAndDevelopmentCostsTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/RevenueFromContractsWithCustomersTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#RevenueFromContractsWithCustomersTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/SegmentReportingTables" xlink:type="simple" xlink:href="tlx-20241231.xsd#SegmentReportingTables" />
  <link:roleRef roleURI="http://telixpharma.com/role/MaterialAccountingPolicyInformationPolicies" xlink:type="simple" xlink:href="tlx-20241231.xsd#MaterialAccountingPolicyInformationPolicies" />
  <link:roleRef roleURI="http://telixpharma.com/role/CybersecurityRiskManagementAndStrategyDisclosure" xlink:type="simple" xlink:href="tlx-20241231.xsd#CybersecurityRiskManagementAndStrategyDisclosure" />
  <link:roleRef roleURI="http://telixpharma.com/role/EventsOccurringAfterReportingPeriod" xlink:type="simple" xlink:href="tlx-20241231.xsd#EventsOccurringAfterReportingPeriod" />
  <link:roleRef roleURI="http://telixpharma.com/role/RemunerationOfAuditor" xlink:type="simple" xlink:href="tlx-20241231.xsd#RemunerationOfAuditor" />
  <link:roleRef roleURI="http://telixpharma.com/role/RelatedPartyTransactions" xlink:type="simple" xlink:href="tlx-20241231.xsd#RelatedPartyTransactions" />
  <link:roleRef roleURI="http://telixpharma.com/role/Commitments" xlink:type="simple" xlink:href="tlx-20241231.xsd#Commitments" />
  <link:roleRef roleURI="http://telixpharma.com/role/ContingentLiabilities" xlink:type="simple" xlink:href="tlx-20241231.xsd#ContingentLiabilities" />
  <link:roleRef roleURI="http://telixpharma.com/role/FinancialRiskManagement" xlink:type="simple" xlink:href="tlx-20241231.xsd#FinancialRiskManagement" />
  <link:roleRef roleURI="http://telixpharma.com/role/CashFlowInformation" xlink:type="simple" xlink:href="tlx-20241231.xsd#CashFlowInformation" />
  <link:roleRef roleURI="http://telixpharma.com/role/SharebasedPayments" xlink:type="simple" xlink:href="tlx-20241231.xsd#SharebasedPayments" />
  <link:roleRef roleURI="http://telixpharma.com/role/Equity" xlink:type="simple" xlink:href="tlx-20241231.xsd#Equity" />
  <link:roleRef roleURI="http://telixpharma.com/role/EmployeeBenefitObligations" xlink:type="simple" xlink:href="tlx-20241231.xsd#EmployeeBenefitObligations" />
  <link:roleRef roleURI="http://telixpharma.com/role/ContingentConsideration" xlink:type="simple" xlink:href="tlx-20241231.xsd#ContingentConsideration" />
  <link:roleRef roleURI="http://telixpharma.com/role/Provisions" xlink:type="simple" xlink:href="tlx-20241231.xsd#Provisions" />
  <link:roleRef roleURI="http://telixpharma.com/role/LeaseLiabilities" xlink:type="simple" xlink:href="tlx-20241231.xsd#LeaseLiabilities" />
  <link:roleRef roleURI="http://telixpharma.com/role/ContractLiabilities" xlink:type="simple" xlink:href="tlx-20241231.xsd#ContractLiabilities" />
  <link:roleRef roleURI="http://telixpharma.com/role/Borrowings" xlink:type="simple" xlink:href="tlx-20241231.xsd#Borrowings" />
  <link:roleRef roleURI="http://telixpharma.com/role/TradeAndOtherPayables" xlink:type="simple" xlink:href="tlx-20241231.xsd#TradeAndOtherPayables" />
  <link:roleRef roleURI="http://telixpharma.com/role/Acquisitions" xlink:type="simple" xlink:href="tlx-20241231.xsd#Acquisitions" />
  <link:roleRef roleURI="http://telixpharma.com/role/IntangibleAssets" xlink:type="simple" xlink:href="tlx-20241231.xsd#IntangibleAssets" />
  <link:roleRef roleURI="http://telixpharma.com/role/RightofuseAssets" xlink:type="simple" xlink:href="tlx-20241231.xsd#RightofuseAssets" />
  <link:roleRef roleURI="http://telixpharma.com/role/PropertyPlantAndEquipment" xlink:type="simple" xlink:href="tlx-20241231.xsd#PropertyPlantAndEquipment" />
  <link:roleRef roleURI="http://telixpharma.com/role/DeferredTaxAssetsAndLiabilities" xlink:type="simple" xlink:href="tlx-20241231.xsd#DeferredTaxAssetsAndLiabilities" />
  <link:roleRef roleURI="http://telixpharma.com/role/FinancialAssets" xlink:type="simple" xlink:href="tlx-20241231.xsd#FinancialAssets" />
  <link:roleRef roleURI="http://telixpharma.com/role/OtherCurrentAssets" xlink:type="simple" xlink:href="tlx-20241231.xsd#OtherCurrentAssets" />
  <link:roleRef roleURI="http://telixpharma.com/role/Inventories" xlink:type="simple" xlink:href="tlx-20241231.xsd#Inventories" />
  <link:roleRef roleURI="http://telixpharma.com/role/TradeAndOtherReceivables" xlink:type="simple" xlink:href="tlx-20241231.xsd#TradeAndOtherReceivables" />
  <link:roleRef roleURI="http://telixpharma.com/role/EarningsPerShare" xlink:type="simple" xlink:href="tlx-20241231.xsd#EarningsPerShare" />
  <link:roleRef roleURI="http://telixpharma.com/role/IncomeTaxExpenseBenefit" xlink:type="simple" xlink:href="tlx-20241231.xsd#IncomeTaxExpenseBenefit" />
  <link:roleRef roleURI="http://telixpharma.com/role/FinanceCosts" xlink:type="simple" xlink:href="tlx-20241231.xsd#FinanceCosts" />
  <link:roleRef roleURI="http://telixpharma.com/role/OtherGainsLossesNet" xlink:type="simple" xlink:href="tlx-20241231.xsd#OtherGainsLossesNet" />
  <link:roleRef roleURI="http://telixpharma.com/role/DepreciationAndAmortization" xlink:type="simple" xlink:href="tlx-20241231.xsd#DepreciationAndAmortization" />
  <link:roleRef roleURI="http://telixpharma.com/role/EmploymentCosts" xlink:type="simple" xlink:href="tlx-20241231.xsd#EmploymentCosts" />
  <link:roleRef roleURI="http://telixpharma.com/role/GeneralAndAdministrationCosts" xlink:type="simple" xlink:href="tlx-20241231.xsd#GeneralAndAdministrationCosts" />
  <link:roleRef roleURI="http://telixpharma.com/role/ResearchAndDevelopmentCosts" xlink:type="simple" xlink:href="tlx-20241231.xsd#ResearchAndDevelopmentCosts" />
  <link:roleRef roleURI="http://telixpharma.com/role/RevenueFromContractsWithCustomers" xlink:type="simple" xlink:href="tlx-20241231.xsd#RevenueFromContractsWithCustomers" />
  <link:roleRef roleURI="http://telixpharma.com/role/SegmentReporting" xlink:type="simple" xlink:href="tlx-20241231.xsd#SegmentReporting" />
  <link:roleRef roleURI="http://telixpharma.com/role/MaterialAccountingPolicyInformation" xlink:type="simple" xlink:href="tlx-20241231.xsd#MaterialAccountingPolicyInformation" />
  <link:roleRef roleURI="http://telixpharma.com/role/CorporateInformation" xlink:type="simple" xlink:href="tlx-20241231.xsd#CorporateInformation" />
  <link:roleRef roleURI="http://telixpharma.com/role/ConsolidatedStatementOfCashFlows" xlink:type="simple" xlink:href="tlx-20241231.xsd#ConsolidatedStatementOfCashFlows" />
  <link:roleRef roleURI="http://telixpharma.com/role/ConsolidatedStatementOfChangesInEquity" xlink:type="simple" xlink:href="tlx-20241231.xsd#ConsolidatedStatementOfChangesInEquity" />
  <link:roleRef roleURI="http://telixpharma.com/role/ConsolidatedStatementOfFinancialPosition" xlink:type="simple" xlink:href="tlx-20241231.xsd#ConsolidatedStatementOfFinancialPosition" />
  <link:roleRef roleURI="http://telixpharma.com/role/ConsolidatedStatementOfComprehensiveIncomeOrLoss" xlink:type="simple" xlink:href="tlx-20241231.xsd#ConsolidatedStatementOfComprehensiveIncomeOrLoss" />
  <link:roleRef roleURI="http://telixpharma.com/role/DocumentAndEntityInformation" xlink:type="simple" xlink:href="tlx-20241231.xsd#DocumentAndEntityInformation" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" />
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/DocumentAndEntityInformation">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressesLineItems" xlink:label="EntityAddressesLineItems" xlink:title="EntityAddressesLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentType" xlink:label="DocumentType" xlink:title="DocumentType" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="DocumentType" xlink:title="definition: EntityAddressesLineItems to DocumentType" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AmendmentFlag" xlink:label="AmendmentFlag" xlink:title="AmendmentFlag" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="AmendmentFlag" xlink:title="definition: EntityAddressesLineItems to AmendmentFlag" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentRegistrationStatement" xlink:label="DocumentRegistrationStatement" xlink:title="DocumentRegistrationStatement" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="DocumentRegistrationStatement" xlink:title="definition: EntityAddressesLineItems to DocumentRegistrationStatement" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentAnnualReport" xlink:label="DocumentAnnualReport" xlink:title="DocumentAnnualReport" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="DocumentAnnualReport" xlink:title="definition: EntityAddressesLineItems to DocumentAnnualReport" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentPeriodEndDate" xlink:label="DocumentPeriodEndDate" xlink:title="DocumentPeriodEndDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="DocumentPeriodEndDate" xlink:title="definition: EntityAddressesLineItems to DocumentPeriodEndDate" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_CurrentFiscalYearEndDate" xlink:label="CurrentFiscalYearEndDate" xlink:title="CurrentFiscalYearEndDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="CurrentFiscalYearEndDate" xlink:title="definition: EntityAddressesLineItems to CurrentFiscalYearEndDate" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentFiscalYearFocus" xlink:label="DocumentFiscalYearFocus" xlink:title="DocumentFiscalYearFocus" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="DocumentFiscalYearFocus" xlink:title="definition: EntityAddressesLineItems to DocumentFiscalYearFocus" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentFiscalPeriodFocus" xlink:label="DocumentFiscalPeriodFocus" xlink:title="DocumentFiscalPeriodFocus" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="DocumentFiscalPeriodFocus" xlink:title="definition: EntityAddressesLineItems to DocumentFiscalPeriodFocus" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentTransitionReport" xlink:label="DocumentTransitionReport" xlink:title="DocumentTransitionReport" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="DocumentTransitionReport" xlink:title="definition: EntityAddressesLineItems to DocumentTransitionReport" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentShellCompanyReport" xlink:label="DocumentShellCompanyReport" xlink:title="DocumentShellCompanyReport" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="DocumentShellCompanyReport" xlink:title="definition: EntityAddressesLineItems to DocumentShellCompanyReport" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityFileNumber" xlink:label="EntityFileNumber" xlink:title="EntityFileNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="EntityFileNumber" xlink:title="definition: EntityAddressesLineItems to EntityFileNumber" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityRegistrantName" xlink:label="EntityRegistrantName" xlink:title="EntityRegistrantName" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="EntityRegistrantName" xlink:title="definition: EntityAddressesLineItems to EntityRegistrantName" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityCentralIndexKey" xlink:label="EntityCentralIndexKey" xlink:title="EntityCentralIndexKey" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="EntityCentralIndexKey" xlink:title="definition: EntityAddressesLineItems to EntityCentralIndexKey" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityIncorporationStateCountryCode" xlink:label="EntityIncorporationStateCountryCode" xlink:title="EntityIncorporationStateCountryCode" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="EntityIncorporationStateCountryCode" xlink:title="definition: EntityAddressesLineItems to EntityIncorporationStateCountryCode" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_ContactPersonnelName" xlink:label="ContactPersonnelName" xlink:title="ContactPersonnelName" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="ContactPersonnelName" xlink:title="definition: EntityAddressesLineItems to ContactPersonnelName" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressAddressLine1" xlink:label="EntityAddressAddressLine1" xlink:title="EntityAddressAddressLine1" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="EntityAddressAddressLine1" xlink:title="definition: EntityAddressesLineItems to EntityAddressAddressLine1" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressCityOrTown" xlink:label="EntityAddressCityOrTown" xlink:title="EntityAddressCityOrTown" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="EntityAddressCityOrTown" xlink:title="definition: EntityAddressesLineItems to EntityAddressCityOrTown" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressCountry" xlink:label="EntityAddressCountry" xlink:title="EntityAddressCountry" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="EntityAddressCountry" xlink:title="definition: EntityAddressesLineItems to EntityAddressCountry" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressPostalZipCode" xlink:label="EntityAddressPostalZipCode" xlink:title="EntityAddressPostalZipCode" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="EntityAddressPostalZipCode" xlink:title="definition: EntityAddressesLineItems to EntityAddressPostalZipCode" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_CityAreaCode" xlink:label="CityAreaCode" xlink:title="CityAreaCode" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="CityAreaCode" xlink:title="definition: EntityAddressesLineItems to CityAreaCode" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_LocalPhoneNumber" xlink:label="LocalPhoneNumber" xlink:title="LocalPhoneNumber" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="LocalPhoneNumber" xlink:title="definition: EntityAddressesLineItems to LocalPhoneNumber" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_Security12bTitle" xlink:label="Security12bTitle" xlink:title="Security12bTitle" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="Security12bTitle" xlink:title="definition: EntityAddressesLineItems to Security12bTitle" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_TradingSymbol" xlink:label="TradingSymbol" xlink:title="TradingSymbol" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="TradingSymbol" xlink:title="definition: EntityAddressesLineItems to TradingSymbol" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_SecurityExchangeName" xlink:label="SecurityExchangeName" xlink:title="SecurityExchangeName" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="SecurityExchangeName" xlink:title="definition: EntityAddressesLineItems to SecurityExchangeName" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityCommonStockSharesOutstanding" xlink:label="EntityCommonStockSharesOutstanding" xlink:title="EntityCommonStockSharesOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="EntityCommonStockSharesOutstanding" xlink:title="definition: EntityAddressesLineItems to EntityCommonStockSharesOutstanding" order="25.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityWellKnownSeasonedIssuer" xlink:label="EntityWellKnownSeasonedIssuer" xlink:title="EntityWellKnownSeasonedIssuer" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="EntityWellKnownSeasonedIssuer" xlink:title="definition: EntityAddressesLineItems to EntityWellKnownSeasonedIssuer" order="26.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityVoluntaryFilers" xlink:label="EntityVoluntaryFilers" xlink:title="EntityVoluntaryFilers" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="EntityVoluntaryFilers" xlink:title="definition: EntityAddressesLineItems to EntityVoluntaryFilers" order="27.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityCurrentReportingStatus" xlink:label="EntityCurrentReportingStatus" xlink:title="EntityCurrentReportingStatus" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="EntityCurrentReportingStatus" xlink:title="definition: EntityAddressesLineItems to EntityCurrentReportingStatus" order="28.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityInteractiveDataCurrent" xlink:label="EntityInteractiveDataCurrent" xlink:title="EntityInteractiveDataCurrent" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="EntityInteractiveDataCurrent" xlink:title="definition: EntityAddressesLineItems to EntityInteractiveDataCurrent" order="29.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityFilerCategory" xlink:label="EntityFilerCategory" xlink:title="EntityFilerCategory" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="EntityFilerCategory" xlink:title="definition: EntityAddressesLineItems to EntityFilerCategory" order="30.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityEmergingGrowthCompany" xlink:label="EntityEmergingGrowthCompany" xlink:title="EntityEmergingGrowthCompany" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="EntityEmergingGrowthCompany" xlink:title="definition: EntityAddressesLineItems to EntityEmergingGrowthCompany" order="31.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityExTransitionPeriod" xlink:label="EntityExTransitionPeriod" xlink:title="EntityExTransitionPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="EntityExTransitionPeriod" xlink:title="definition: EntityAddressesLineItems to EntityExTransitionPeriod" order="32.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_IcfrAuditorAttestationFlag" xlink:label="IcfrAuditorAttestationFlag" xlink:title="IcfrAuditorAttestationFlag" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="IcfrAuditorAttestationFlag" xlink:title="definition: EntityAddressesLineItems to IcfrAuditorAttestationFlag" order="33.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentFinStmtErrorCorrectionFlag" xlink:label="DocumentFinStmtErrorCorrectionFlag" xlink:title="DocumentFinStmtErrorCorrectionFlag" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="DocumentFinStmtErrorCorrectionFlag" xlink:title="definition: EntityAddressesLineItems to DocumentFinStmtErrorCorrectionFlag" order="34.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_DocumentAccountingStandard" xlink:label="DocumentAccountingStandard" xlink:title="DocumentAccountingStandard" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="DocumentAccountingStandard" xlink:title="definition: EntityAddressesLineItems to DocumentAccountingStandard" order="35.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityShellCompany" xlink:label="EntityShellCompany" xlink:title="EntityShellCompany" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="EntityShellCompany" xlink:title="definition: EntityAddressesLineItems to EntityShellCompany" order="36.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AuditorFirmId" xlink:label="AuditorFirmId" xlink:title="AuditorFirmId" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="AuditorFirmId" xlink:title="definition: EntityAddressesLineItems to AuditorFirmId" order="37.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AuditorName" xlink:label="AuditorName" xlink:title="AuditorName" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="AuditorName" xlink:title="definition: EntityAddressesLineItems to AuditorName" order="38.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AuditorLocation" xlink:label="AuditorLocation" xlink:title="AuditorLocation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityAddressesLineItems" xlink:to="AuditorLocation" xlink:title="definition: EntityAddressesLineItems to AuditorLocation" order="39.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressesTable" xlink:label="EntityAddressesTable" xlink:title="EntityAddressesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="EntityAddressesLineItems" xlink:to="EntityAddressesTable" xlink:title="definition: EntityAddressesLineItems to EntityAddressesTable" order="40.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_EntityAddressesAddressTypeAxis" xlink:label="EntityAddressesAddressTypeAxis" xlink:title="EntityAddressesAddressTypeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="EntityAddressesTable" xlink:to="EntityAddressesAddressTypeAxis" xlink:title="definition: EntityAddressesTable to EntityAddressesAddressTypeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AddressTypeDomain" xlink:label="AddressTypeDomain" xlink:title="AddressTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="EntityAddressesAddressTypeAxis" xlink:to="AddressTypeDomain" xlink:title="definition: EntityAddressesAddressTypeAxis to AddressTypeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_AddressTypeDomain" xlink:label="AddressTypeDomain_2" xlink:title="AddressTypeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="EntityAddressesAddressTypeAxis" xlink:to="AddressTypeDomain_2" xlink:title="definition: EntityAddressesAddressTypeAxis to AddressTypeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2024/dei-2024.xsd#dei_BusinessContactMember" xlink:label="BusinessContactMember" xlink:title="BusinessContactMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AddressTypeDomain" xlink:to="BusinessContactMember" xlink:title="definition: AddressTypeDomain to BusinessContactMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ConsolidatedStatementOfComprehensiveIncomeOrLoss" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ConsolidatedStatementOfFinancialPosition" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ConsolidatedStatementOfChangesInEquity">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_StatementOfChangesInEquityLineItems" xlink:label="StatementOfChangesInEquityLineItems" xlink:title="StatementOfChangesInEquityLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ChangesInEquityAbstract" xlink:label="ChangesInEquityAbstract" xlink:title="ChangesInEquityAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementOfChangesInEquityLineItems" xlink:to="ChangesInEquityAbstract" xlink:title="definition: StatementOfChangesInEquityLineItems to ChangesInEquityAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Equity" xlink:label="Equity" xlink:title="Equity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementOfChangesInEquityLineItems" xlink:to="Equity" xlink:title="definition: StatementOfChangesInEquityLineItems to Equity" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProfitLoss" xlink:label="ProfitLoss" xlink:title="ProfitLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementOfChangesInEquityLineItems" xlink:to="ProfitLoss" xlink:title="definition: StatementOfChangesInEquityLineItems to ProfitLoss" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherComprehensiveIncome" xlink:label="OtherComprehensiveIncome" xlink:title="OtherComprehensiveIncome" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementOfChangesInEquityLineItems" xlink:to="OtherComprehensiveIncome" xlink:title="definition: StatementOfChangesInEquityLineItems to OtherComprehensiveIncome" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComprehensiveIncome" xlink:label="ComprehensiveIncome" xlink:title="ComprehensiveIncome" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementOfChangesInEquityLineItems" xlink:to="ComprehensiveIncome" xlink:title="definition: StatementOfChangesInEquityLineItems to ComprehensiveIncome" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IssueOfEquity" xlink:label="IssueOfEquity" xlink:title="IssueOfEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementOfChangesInEquityLineItems" xlink:to="IssueOfEquity" xlink:title="definition: StatementOfChangesInEquityLineItems to IssueOfEquity" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseInTransactionCostsArisingOnNewShareIssues" xlink:label="IncreaseDecreaseInTransactionCostsArisingOnNewShareIssues" xlink:title="IncreaseDecreaseInTransactionCostsArisingOnNewShareIssues" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementOfChangesInEquityLineItems" xlink:to="IncreaseDecreaseInTransactionCostsArisingOnNewShareIssues" xlink:title="definition: StatementOfChangesInEquityLineItems to IncreaseDecreaseInTransactionCostsArisingOnNewShareIssues" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughExerciseOfOptions" xlink:label="IncreaseDecreaseThroughExerciseOfOptions" xlink:title="IncreaseDecreaseThroughExerciseOfOptions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementOfChangesInEquityLineItems" xlink:to="IncreaseDecreaseThroughExerciseOfOptions" xlink:title="definition: StatementOfChangesInEquityLineItems to IncreaseDecreaseThroughExerciseOfOptions" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IssueOfConvertibleInstruments" xlink:label="IssueOfConvertibleInstruments" xlink:title="IssueOfConvertibleInstruments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementOfChangesInEquityLineItems" xlink:to="IssueOfConvertibleInstruments" xlink:title="definition: StatementOfChangesInEquityLineItems to IssueOfConvertibleInstruments" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseThroughTransactionCostsArisingOnConvertibleBondsIssue" xlink:label="IncreaseDecreaseThroughTransactionCostsArisingOnConvertibleBondsIssue" xlink:title="IncreaseDecreaseThroughTransactionCostsArisingOnConvertibleBondsIssue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementOfChangesInEquityLineItems" xlink:to="IncreaseDecreaseThroughTransactionCostsArisingOnConvertibleBondsIssue" xlink:title="definition: StatementOfChangesInEquityLineItems to IncreaseDecreaseThroughTransactionCostsArisingOnConvertibleBondsIssue" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughSharebasedPaymentTransactions" xlink:label="IncreaseDecreaseThroughSharebasedPaymentTransactions" xlink:title="IncreaseDecreaseThroughSharebasedPaymentTransactions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementOfChangesInEquityLineItems" xlink:to="IncreaseDecreaseThroughSharebasedPaymentTransactions" xlink:title="definition: StatementOfChangesInEquityLineItems to IncreaseDecreaseThroughSharebasedPaymentTransactions" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseThroughShareBasedPaymentTransactionsAssociatedWithAcquisitionsEquity" xlink:label="IncreaseDecreaseThroughShareBasedPaymentTransactionsAssociatedWithAcquisitionsEquity" xlink:title="IncreaseDecreaseThroughShareBasedPaymentTransactionsAssociatedWithAcquisitionsEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementOfChangesInEquityLineItems" xlink:to="IncreaseDecreaseThroughShareBasedPaymentTransactionsAssociatedWithAcquisitionsEquity" xlink:title="definition: StatementOfChangesInEquityLineItems to IncreaseDecreaseThroughShareBasedPaymentTransactionsAssociatedWithAcquisitionsEquity" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseThroughTransferOnExerciseOfOptionsEquity" xlink:label="IncreaseDecreaseThroughTransferOnExerciseOfOptionsEquity" xlink:title="IncreaseDecreaseThroughTransferOnExerciseOfOptionsEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementOfChangesInEquityLineItems" xlink:to="IncreaseDecreaseThroughTransferOnExerciseOfOptionsEquity" xlink:title="definition: StatementOfChangesInEquityLineItems to IncreaseDecreaseThroughTransferOnExerciseOfOptionsEquity" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ChangesInEquity" xlink:label="ChangesInEquity" xlink:title="ChangesInEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="StatementOfChangesInEquityLineItems" xlink:to="ChangesInEquity" xlink:title="definition: StatementOfChangesInEquityLineItems to ChangesInEquity" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_StatementOfChangesInEquityTable" xlink:label="StatementOfChangesInEquityTable" xlink:title="StatementOfChangesInEquityTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="StatementOfChangesInEquityLineItems" xlink:to="StatementOfChangesInEquityTable" xlink:title="definition: StatementOfChangesInEquityLineItems to StatementOfChangesInEquityTable" order="15.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityAxis" xlink:label="ComponentsOfEquityAxis" xlink:title="ComponentsOfEquityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="StatementOfChangesInEquityTable" xlink:to="ComponentsOfEquityAxis" xlink:title="definition: StatementOfChangesInEquityTable to ComponentsOfEquityAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ComponentsOfEquityDomain" xlink:title="ComponentsOfEquityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ComponentsOfEquityAxis" xlink:to="ComponentsOfEquityDomain" xlink:title="definition: ComponentsOfEquityAxis to ComponentsOfEquityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ComponentsOfEquityDomain_2" xlink:title="ComponentsOfEquityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ComponentsOfEquityAxis" xlink:to="ComponentsOfEquityDomain_2" xlink:title="definition: ComponentsOfEquityAxis to ComponentsOfEquityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IssuedCapitalMember" xlink:label="IssuedCapitalMember" xlink:title="IssuedCapitalMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComponentsOfEquityDomain" xlink:to="IssuedCapitalMember" xlink:title="definition: ComponentsOfEquityDomain to IssuedCapitalMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CapitalReserveMember" xlink:label="CapitalReserveMember" xlink:title="CapitalReserveMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComponentsOfEquityDomain" xlink:to="CapitalReserveMember" xlink:title="definition: ComponentsOfEquityDomain to CapitalReserveMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherReservesMember" xlink:label="OtherReservesMember" xlink:title="OtherReservesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComponentsOfEquityDomain" xlink:to="OtherReservesMember" xlink:title="definition: ComponentsOfEquityDomain to OtherReservesMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RetainedEarningsMember" xlink:label="RetainedEarningsMember" xlink:title="RetainedEarningsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComponentsOfEquityDomain" xlink:to="RetainedEarningsMember" xlink:title="definition: ComponentsOfEquityDomain to RetainedEarningsMember" order="4.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ConsolidatedStatementOfCashFlows" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/CorporateInformation" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/MaterialAccountingPolicyInformation" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/SegmentReporting" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/RevenueFromContractsWithCustomers" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ResearchAndDevelopmentCosts" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/GeneralAndAdministrationCosts" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EmploymentCosts" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/DepreciationAndAmortization" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/OtherGainsLossesNet" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/FinanceCosts" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/IncomeTaxExpenseBenefit" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EarningsPerShare" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/TradeAndOtherReceivables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/Inventories" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/OtherCurrentAssets" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/FinancialAssets" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/DeferredTaxAssetsAndLiabilities" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/PropertyPlantAndEquipment" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/RightofuseAssets" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/IntangibleAssets" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/Acquisitions" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/TradeAndOtherPayables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/Borrowings" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ContractLiabilities" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/LeaseLiabilities" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/Provisions" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ContingentConsideration" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EmployeeBenefitObligations" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/Equity" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/SharebasedPayments" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/CashFlowInformation" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/FinancialRiskManagement" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ContingentLiabilities" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/Commitments" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/RelatedPartyTransactions" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/RemunerationOfAuditor" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EventsOccurringAfterReportingPeriod" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/CybersecurityRiskManagementAndStrategyDisclosure" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/MaterialAccountingPolicyInformationPolicies" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/SegmentReportingTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/RevenueFromContractsWithCustomersTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ResearchAndDevelopmentCostsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/GeneralAndAdministrationCostsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EmploymentCostsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/DepreciationAndAmortizationTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/OtherGainsLossesNetTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/FinanceCostsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/IncomeTaxExpenseBenefitTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EarningsPerShareTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/TradeAndOtherReceivablesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/InventoriesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/OtherCurrentAssetsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/FinancialAssetsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/DeferredTaxAssetsAndLiabilitiesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/PropertyPlantAndEquipmentTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/RightofuseAssetsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/IntangibleAssetsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/AcquisitionsTables">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfBusinessCombinationsLineItems" xlink:label="DisclosureOfBusinessCombinationsLineItems" xlink:title="DisclosureOfBusinessCombinationsLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTransactionsRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombinationExplanatory" xlink:label="DisclosureOfTransactionsRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombinationExplanatory" xlink:title="DisclosureOfTransactionsRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombinationExplanatory" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="DisclosureOfTransactionsRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombinationExplanatory" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to DisclosureOfTransactionsRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombinationExplanatory" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfBusinessCombinationsTable" xlink:label="DisclosureOfBusinessCombinationsTable" xlink:title="DisclosureOfBusinessCombinationsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="DisclosureOfBusinessCombinationsTable" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to DisclosureOfBusinessCombinationsTable" order="2.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsAxis" xlink:label="BusinessCombinationsAxis" xlink:title="BusinessCombinationsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfBusinessCombinationsTable" xlink:to="BusinessCombinationsAxis" xlink:title="definition: DisclosureOfBusinessCombinationsTable to BusinessCombinationsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain_2" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain_2" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsMember" xlink:label="BusinessCombinationsMember" xlink:title="BusinessCombinationsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="BusinessCombinationsMember" xlink:title="definition: BusinessCombinationsDomain to BusinessCombinationsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IsoTherapeuticsGroupLLCMember" xlink:label="IsoTherapeuticsGroupLLCMember" xlink:title="IsoTherapeuticsGroupLLCMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsMember" xlink:to="IsoTherapeuticsGroupLLCMember" xlink:title="definition: BusinessCombinationsMember to IsoTherapeuticsGroupLLCMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ARTMSIncMember" xlink:label="ARTMSIncMember" xlink:title="ARTMSIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsMember" xlink:to="ARTMSIncMember" xlink:title="definition: BusinessCombinationsMember to ARTMSIncMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_QSAMBiosciencesIncMember" xlink:label="QSAMBiosciencesIncMember" xlink:title="QSAMBiosciencesIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsMember" xlink:to="QSAMBiosciencesIncMember" xlink:title="definition: BusinessCombinationsMember to QSAMBiosciencesIncMember" order="3.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/TradeAndOtherPayablesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/BorrowingsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ContractLiabilitiesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/LeaseLiabilitiesTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ProvisionsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ContingentConsiderationTables">
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DetailedInformationAboutContingentConsiderationLineItems" xlink:label="DetailedInformationAboutContingentConsiderationLineItems" xlink:title="DetailedInformationAboutContingentConsiderationLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ScheduleOfContingentConsiderationExplanatoryTableTextBlock" xlink:label="ScheduleOfContingentConsiderationExplanatoryTableTextBlock" xlink:title="ScheduleOfContingentConsiderationExplanatoryTableTextBlock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="ScheduleOfContingentConsiderationExplanatoryTableTextBlock" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to ScheduleOfContingentConsiderationExplanatoryTableTextBlock" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ScheduleOfContingentConsiderationValuationTableTextBlock" xlink:label="ScheduleOfContingentConsiderationValuationTableTextBlock" xlink:title="ScheduleOfContingentConsiderationValuationTableTextBlock" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="ScheduleOfContingentConsiderationValuationTableTextBlock" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to ScheduleOfContingentConsiderationValuationTableTextBlock" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DetailedInformationAboutContingentConsiderationTable" xlink:label="DetailedInformationAboutContingentConsiderationTable" xlink:title="DetailedInformationAboutContingentConsiderationTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="DetailedInformationAboutContingentConsiderationTable" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to DetailedInformationAboutContingentConsiderationTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsAxis" xlink:label="BusinessCombinationsAxis" xlink:title="BusinessCombinationsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DetailedInformationAboutContingentConsiderationTable" xlink:to="BusinessCombinationsAxis" xlink:title="definition: DetailedInformationAboutContingentConsiderationTable to BusinessCombinationsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain_2" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain_2" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ANMIMember" xlink:label="ANMIMember" xlink:title="ANMIMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="ANMIMember" xlink:title="definition: BusinessCombinationsDomain to ANMIMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TheraPharmMember" xlink:label="TheraPharmMember" xlink:title="TheraPharmMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="TheraPharmMember" xlink:title="definition: BusinessCombinationsDomain to TheraPharmMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_OptimalTracersMember" xlink:label="OptimalTracersMember" xlink:title="OptimalTracersMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="OptimalTracersMember" xlink:title="definition: BusinessCombinationsDomain to OptimalTracersMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ARTMSMember" xlink:label="ARTMSMember" xlink:title="ARTMSMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="ARTMSMember" xlink:title="definition: BusinessCombinationsDomain to ARTMSMember" order="4.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EmployeeBenefitObligationsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EquityTables">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfClassesOfShareCapitalLineItems" xlink:label="DisclosureOfClassesOfShareCapitalLineItems" xlink:title="DisclosureOfClassesOfShareCapitalLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfClassesOfShareCapitalExplanatory" xlink:label="DisclosureOfClassesOfShareCapitalExplanatory" xlink:title="DisclosureOfClassesOfShareCapitalExplanatory" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="DisclosureOfClassesOfShareCapitalExplanatory" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to DisclosureOfClassesOfShareCapitalExplanatory" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfClassesOfShareCapitalTable" xlink:label="DisclosureOfClassesOfShareCapitalTable" xlink:title="DisclosureOfClassesOfShareCapitalTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="DisclosureOfClassesOfShareCapitalTable" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to DisclosureOfClassesOfShareCapitalTable" order="2.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityAxis" xlink:label="ComponentsOfEquityAxis" xlink:title="ComponentsOfEquityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfClassesOfShareCapitalTable" xlink:to="ComponentsOfEquityAxis" xlink:title="definition: DisclosureOfClassesOfShareCapitalTable to ComponentsOfEquityAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ComponentsOfEquityDomain" xlink:title="ComponentsOfEquityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ComponentsOfEquityAxis" xlink:to="ComponentsOfEquityDomain" xlink:title="definition: ComponentsOfEquityAxis to ComponentsOfEquityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ComponentsOfEquityDomain_2" xlink:title="ComponentsOfEquityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ComponentsOfEquityAxis" xlink:to="ComponentsOfEquityDomain_2" xlink:title="definition: ComponentsOfEquityAxis to ComponentsOfEquityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IssuedCapitalMember" xlink:label="IssuedCapitalMember" xlink:title="IssuedCapitalMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComponentsOfEquityDomain" xlink:to="IssuedCapitalMember" xlink:title="definition: ComponentsOfEquityDomain to IssuedCapitalMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CapitalReserveMember" xlink:label="CapitalReserveMember" xlink:title="CapitalReserveMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComponentsOfEquityDomain" xlink:to="CapitalReserveMember" xlink:title="definition: ComponentsOfEquityDomain to CapitalReserveMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherReservesMember" xlink:label="OtherReservesMember" xlink:title="OtherReservesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComponentsOfEquityDomain" xlink:to="OtherReservesMember" xlink:title="definition: ComponentsOfEquityDomain to OtherReservesMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ReserveOfSharebasedPaymentsMember" xlink:label="ReserveOfSharebasedPaymentsMember" xlink:title="ReserveOfSharebasedPaymentsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComponentsOfEquityDomain" xlink:to="ReserveOfSharebasedPaymentsMember" xlink:title="definition: ComponentsOfEquityDomain to ReserveOfSharebasedPaymentsMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncomeMember" xlink:label="ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncomeMember" xlink:title="ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncomeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComponentsOfEquityDomain" xlink:to="ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncomeMember" xlink:title="definition: ComponentsOfEquityDomain to ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncomeMember" order="5.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/SharebasedPaymentsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/CashFlowInformationTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/FinancialRiskManagementTables">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:label="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:title="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsExplanatory" xlink:label="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsExplanatory" xlink:title="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsExplanatory" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsExplanatory" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsExplanatory" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SensitivityAnalysisForEachTypeOfMarketRisk" xlink:label="SensitivityAnalysisForEachTypeOfMarketRisk" xlink:title="SensitivityAnalysisForEachTypeOfMarketRisk" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="SensitivityAnalysisForEachTypeOfMarketRisk" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to SensitivityAnalysisForEachTypeOfMarketRisk" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:label="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:title="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfRisksAxis" xlink:label="TypesOfRisksAxis" xlink:title="TypesOfRisksAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:to="TypesOfRisksAxis" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable to TypesOfRisksAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfRisksDomain" xlink:label="TypesOfRisksDomain" xlink:title="TypesOfRisksDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TypesOfRisksAxis" xlink:to="TypesOfRisksDomain" xlink:title="definition: TypesOfRisksAxis to TypesOfRisksDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfRisksDomain" xlink:label="TypesOfRisksDomain_2" xlink:title="TypesOfRisksDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TypesOfRisksAxis" xlink:to="TypesOfRisksDomain_2" xlink:title="definition: TypesOfRisksAxis to TypesOfRisksDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrencyRiskMember" xlink:label="CurrencyRiskMember" xlink:title="CurrencyRiskMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TypesOfRisksDomain" xlink:to="CurrencyRiskMember" xlink:title="definition: TypesOfRisksDomain to CurrencyRiskMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/CommitmentsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/RelatedPartyTransactionsTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/RemunerationOfAuditorTables" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EventsOccurringAfterReportingPeriodTables">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:label="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:title="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDetailedInformationAboutBusinessCombinationsExplanatory" xlink:label="DisclosureOfDetailedInformationAboutBusinessCombinationsExplanatory" xlink:title="DisclosureOfDetailedInformationAboutBusinessCombinationsExplanatory" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="DisclosureOfDetailedInformationAboutBusinessCombinationsExplanatory" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to DisclosureOfDetailedInformationAboutBusinessCombinationsExplanatory" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:label="DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:title="DisclosureOfNonadjustingEventsAfterReportingPeriodTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to DisclosureOfNonadjustingEventsAfterReportingPeriodTable" order="2.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsAxis" xlink:label="BusinessCombinationsAxis" xlink:title="BusinessCombinationsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:to="BusinessCombinationsAxis" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodTable to BusinessCombinationsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain_2" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain_2" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_RLSUSAIncMember" xlink:label="RLSUSAIncMember" xlink:title="RLSUSAIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="RLSUSAIncMember" xlink:title="definition: BusinessCombinationsDomain to RLSUSAIncMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/MaterialAccountingPolicyInformationBusinessCombinationsDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/MaterialAccountingPolicyInformationPropertyPlantAndEquipmentDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:label="DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:title="DisclosureOfPropertyPlantAndEquipmentLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PropertyPlantAndEquipmentAbstract" xlink:label="PropertyPlantAndEquipmentAbstract" xlink:title="PropertyPlantAndEquipmentAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentAbstract" xlink:title="definition: DisclosureOfPropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UsefulLifeMeasuredAsPeriodOfTimePropertyPlantAndEquipment" xlink:label="UsefulLifeMeasuredAsPeriodOfTimePropertyPlantAndEquipment" xlink:title="UsefulLifeMeasuredAsPeriodOfTimePropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="UsefulLifeMeasuredAsPeriodOfTimePropertyPlantAndEquipment" xlink:title="definition: DisclosureOfPropertyPlantAndEquipmentLineItems to UsefulLifeMeasuredAsPeriodOfTimePropertyPlantAndEquipment" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfPropertyPlantAndEquipmentTable" xlink:label="DisclosureOfPropertyPlantAndEquipmentTable" xlink:title="DisclosureOfPropertyPlantAndEquipmentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="DisclosureOfPropertyPlantAndEquipmentTable" xlink:title="definition: DisclosureOfPropertyPlantAndEquipmentLineItems to DisclosureOfPropertyPlantAndEquipmentTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:label="ClassesOfPropertyPlantAndEquipmentAxis" xlink:title="ClassesOfPropertyPlantAndEquipmentAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfPropertyPlantAndEquipmentTable" xlink:to="ClassesOfPropertyPlantAndEquipmentAxis" xlink:title="definition: DisclosureOfPropertyPlantAndEquipmentTable to ClassesOfPropertyPlantAndEquipmentAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:label="ClassesOfPropertyPlantAndEquipmentDomain" xlink:title="ClassesOfPropertyPlantAndEquipmentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ClassesOfPropertyPlantAndEquipmentAxis" xlink:to="ClassesOfPropertyPlantAndEquipmentDomain" xlink:title="definition: ClassesOfPropertyPlantAndEquipmentAxis to ClassesOfPropertyPlantAndEquipmentDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:label="ClassesOfPropertyPlantAndEquipmentDomain_2" xlink:title="ClassesOfPropertyPlantAndEquipmentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassesOfPropertyPlantAndEquipmentAxis" xlink:to="ClassesOfPropertyPlantAndEquipmentDomain_2" xlink:title="definition: ClassesOfPropertyPlantAndEquipmentAxis to ClassesOfPropertyPlantAndEquipmentDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BuildingsMember" xlink:label="BuildingsMember" xlink:title="BuildingsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="BuildingsMember" xlink:title="definition: ClassesOfPropertyPlantAndEquipmentDomain to BuildingsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PropertyPlantAndEquipmentMember" xlink:label="PropertyPlantAndEquipmentMember" xlink:title="PropertyPlantAndEquipmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="PropertyPlantAndEquipmentMember" xlink:title="definition: ClassesOfPropertyPlantAndEquipmentDomain to PropertyPlantAndEquipmentMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FixturesAndFittingsMember" xlink:label="FixturesAndFittingsMember" xlink:title="FixturesAndFittingsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="FixturesAndFittingsMember" xlink:title="definition: ClassesOfPropertyPlantAndEquipmentDomain to FixturesAndFittingsMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_LeasedPlantAndEquipmentMember" xlink:label="LeasedPlantAndEquipmentMember" xlink:title="LeasedPlantAndEquipmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="LeasedPlantAndEquipmentMember" xlink:title="definition: ClassesOfPropertyPlantAndEquipmentDomain to LeasedPlantAndEquipmentMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfPropertyPlantAndEquipmentTable" xlink:to="RangeAxis" xlink:title="definition: DisclosureOfPropertyPlantAndEquipmentTable to RangeAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="RangeDomain" xlink:title="RangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeDomain" xlink:title="definition: RangeAxis to RangeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="RangeDomain_2" xlink:title="RangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeDomain_2" xlink:title="definition: RangeAxis to RangeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BottomOfRangeMember" xlink:label="BottomOfRangeMember" xlink:title="BottomOfRangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeDomain" xlink:to="BottomOfRangeMember" xlink:title="definition: RangeDomain to BottomOfRangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TopOfRangeMember" xlink:label="TopOfRangeMember" xlink:title="TopOfRangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeDomain" xlink:to="TopOfRangeMember" xlink:title="definition: RangeDomain to TopOfRangeMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/MaterialAccountingPolicyInformationIntangibleAssetsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfIntangibleAssetsLineItems" xlink:label="DisclosureOfIntangibleAssetsLineItems" xlink:title="DisclosureOfIntangibleAssetsLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IntangibleAssetsOtherThanGoodwillAbstract" xlink:label="IntangibleAssetsOtherThanGoodwillAbstract" xlink:title="IntangibleAssetsOtherThanGoodwillAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfIntangibleAssetsLineItems" xlink:to="IntangibleAssetsOtherThanGoodwillAbstract" xlink:title="definition: DisclosureOfIntangibleAssetsLineItems to IntangibleAssetsOtherThanGoodwillAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UsefulLifeMeasuredAsPeriodOfTimeIntangibleAssetsOtherThanGoodwill" xlink:label="UsefulLifeMeasuredAsPeriodOfTimeIntangibleAssetsOtherThanGoodwill" xlink:title="UsefulLifeMeasuredAsPeriodOfTimeIntangibleAssetsOtherThanGoodwill" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfIntangibleAssetsLineItems" xlink:to="UsefulLifeMeasuredAsPeriodOfTimeIntangibleAssetsOtherThanGoodwill" xlink:title="definition: DisclosureOfIntangibleAssetsLineItems to UsefulLifeMeasuredAsPeriodOfTimeIntangibleAssetsOtherThanGoodwill" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfIntangibleAssetsTable" xlink:label="DisclosureOfIntangibleAssetsTable" xlink:title="DisclosureOfIntangibleAssetsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfIntangibleAssetsLineItems" xlink:to="DisclosureOfIntangibleAssetsTable" xlink:title="definition: DisclosureOfIntangibleAssetsLineItems to DisclosureOfIntangibleAssetsTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillAxis" xlink:label="ClassesOfIntangibleAssetsOtherThanGoodwillAxis" xlink:title="ClassesOfIntangibleAssetsOtherThanGoodwillAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfIntangibleAssetsTable" xlink:to="ClassesOfIntangibleAssetsOtherThanGoodwillAxis" xlink:title="definition: DisclosureOfIntangibleAssetsTable to ClassesOfIntangibleAssetsOtherThanGoodwillAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:label="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:title="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ClassesOfIntangibleAssetsOtherThanGoodwillAxis" xlink:to="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:title="definition: ClassesOfIntangibleAssetsOtherThanGoodwillAxis to ClassesOfIntangibleAssetsOtherThanGoodwillDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:label="ClassesOfIntangibleAssetsOtherThanGoodwillDomain_2" xlink:title="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassesOfIntangibleAssetsOtherThanGoodwillAxis" xlink:to="ClassesOfIntangibleAssetsOtherThanGoodwillDomain_2" xlink:title="definition: ClassesOfIntangibleAssetsOtherThanGoodwillAxis to ClassesOfIntangibleAssetsOtherThanGoodwillDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PatentsTrademarksLicensesAndCustomerContractsMember" xlink:label="PatentsTrademarksLicensesAndCustomerContractsMember" xlink:title="PatentsTrademarksLicensesAndCustomerContractsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:to="PatentsTrademarksLicensesAndCustomerContractsMember" xlink:title="definition: ClassesOfIntangibleAssetsOtherThanGoodwillDomain to PatentsTrademarksLicensesAndCustomerContractsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IntellectualsPropertiesMember" xlink:label="IntellectualsPropertiesMember" xlink:title="IntellectualsPropertiesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:to="IntellectualsPropertiesMember" xlink:title="definition: ClassesOfIntangibleAssetsOtherThanGoodwillDomain to IntellectualsPropertiesMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfIntangibleAssetsTable" xlink:to="RangeAxis" xlink:title="definition: DisclosureOfIntangibleAssetsTable to RangeAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="RangeDomain" xlink:title="RangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeDomain" xlink:title="definition: RangeAxis to RangeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="RangeDomain_2" xlink:title="RangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeDomain_2" xlink:title="definition: RangeAxis to RangeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BottomOfRangeMember" xlink:label="BottomOfRangeMember" xlink:title="BottomOfRangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeDomain" xlink:to="BottomOfRangeMember" xlink:title="definition: RangeDomain to BottomOfRangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TopOfRangeMember" xlink:label="TopOfRangeMember" xlink:title="TopOfRangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeDomain" xlink:to="TopOfRangeMember" xlink:title="definition: RangeDomain to TopOfRangeMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/MaterialAccountingPolicyInformationTradeAndOtherPayablesDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/MaterialAccountingPolicyInformationRevenueDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:label="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:title="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_SalesOfGoodsAbstract" xlink:label="SalesOfGoodsAbstract" xlink:title="SalesOfGoodsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:to="SalesOfGoodsAbstract" xlink:title="definition: DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems to SalesOfGoodsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_SalesOfGoodsCreditTerm" xlink:label="SalesOfGoodsCreditTerm" xlink:title="SalesOfGoodsCreditTerm" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:to="SalesOfGoodsCreditTerm" xlink:title="definition: DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems to SalesOfGoodsCreditTerm" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable" xlink:label="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable" xlink:title="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:to="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable" xlink:title="definition: DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems to DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable" xlink:to="RangeAxis" xlink:title="definition: DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable to RangeAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="RangeDomain" xlink:title="RangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeDomain" xlink:title="definition: RangeAxis to RangeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="RangeDomain_2" xlink:title="RangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeDomain_2" xlink:title="definition: RangeAxis to RangeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BottomOfRangeMember" xlink:label="BottomOfRangeMember" xlink:title="BottomOfRangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeDomain" xlink:to="BottomOfRangeMember" xlink:title="definition: RangeDomain to BottomOfRangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TopOfRangeMember" xlink:label="TopOfRangeMember" xlink:title="TopOfRangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeDomain" xlink:to="TopOfRangeMember" xlink:title="definition: RangeDomain to TopOfRangeMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/SegmentReportingSegmentPerformanceDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:label="DisclosureOfOperatingSegmentsLineItems" xlink:title="DisclosureOfOperatingSegmentsLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ReportableSegmentsAbstract" xlink:label="ReportableSegmentsAbstract" xlink:title="ReportableSegmentsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="ReportableSegmentsAbstract" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to ReportableSegmentsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RevenueAbstract" xlink:label="RevenueAbstract" xlink:title="RevenueAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="RevenueAbstract" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to RevenueAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RevenueFromContractsWithCustomers" xlink:label="RevenueFromContractsWithCustomers" xlink:title="RevenueFromContractsWithCustomers" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="RevenueFromContractsWithCustomers" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to RevenueFromContractsWithCustomers" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CostOfSales" xlink:label="CostOfSales" xlink:title="CostOfSales" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="CostOfSales" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to CostOfSales" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GrossProfit" xlink:label="GrossProfit" xlink:title="GrossProfit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="GrossProfit" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to GrossProfit" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ResearchAndDevelopmentExpense" xlink:label="ResearchAndDevelopmentExpense" xlink:title="ResearchAndDevelopmentExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="ResearchAndDevelopmentExpense" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to ResearchAndDevelopmentExpense" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_SellingAndMarketingExpenses" xlink:label="SellingAndMarketingExpenses" xlink:title="SellingAndMarketingExpenses" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="SellingAndMarketingExpenses" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to SellingAndMarketingExpenses" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ManufacturingAndDistributionCosts" xlink:label="ManufacturingAndDistributionCosts" xlink:title="ManufacturingAndDistributionCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="ManufacturingAndDistributionCosts" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to ManufacturingAndDistributionCosts" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeneralAndAdministrativeExpense" xlink:label="GeneralAndAdministrativeExpense" xlink:title="GeneralAndAdministrativeExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="GeneralAndAdministrativeExpense" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to GeneralAndAdministrativeExpense" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_OtherGainsLossesInOperatingActivity" xlink:label="OtherGainsLossesInOperatingActivity" xlink:title="OtherGainsLossesInOperatingActivity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="OtherGainsLossesInOperatingActivity" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to OtherGainsLossesInOperatingActivity" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProfitLossFromOperatingActivities" xlink:label="ProfitLossFromOperatingActivities" xlink:title="ProfitLossFromOperatingActivities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="ProfitLossFromOperatingActivities" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to ProfitLossFromOperatingActivities" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherGainsLosses" xlink:label="OtherGainsLosses" xlink:title="OtherGainsLosses" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="OtherGainsLosses" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to OtherGainsLosses" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DepreciationAndAmortisationExpense" xlink:label="DepreciationAndAmortisationExpense" xlink:title="DepreciationAndAmortisationExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="DepreciationAndAmortisationExpense" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to DepreciationAndAmortisationExpense" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AdjustedEarningsBeforeInterestTaxDepreciationAndAmortization" xlink:label="AdjustedEarningsBeforeInterestTaxDepreciationAndAmortization" xlink:title="AdjustedEarningsBeforeInterestTaxDepreciationAndAmortization" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="AdjustedEarningsBeforeInterestTaxDepreciationAndAmortization" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to AdjustedEarningsBeforeInterestTaxDepreciationAndAmortization" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_NumberOfSegments" xlink:label="NumberOfSegments" xlink:title="NumberOfSegments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="NumberOfSegments" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to NumberOfSegments" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOperatingSegmentsTable" xlink:label="DisclosureOfOperatingSegmentsTable" xlink:title="DisclosureOfOperatingSegmentsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="DisclosureOfOperatingSegmentsTable" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to DisclosureOfOperatingSegmentsTable" order="16.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentConsolidationItemsAxis" xlink:label="SegmentConsolidationItemsAxis" xlink:title="SegmentConsolidationItemsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfOperatingSegmentsTable" xlink:to="SegmentConsolidationItemsAxis" xlink:title="definition: DisclosureOfOperatingSegmentsTable to SegmentConsolidationItemsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentConsolidationItemsDomain" xlink:label="SegmentConsolidationItemsDomain" xlink:title="SegmentConsolidationItemsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SegmentConsolidationItemsAxis" xlink:to="SegmentConsolidationItemsDomain" xlink:title="definition: SegmentConsolidationItemsAxis to SegmentConsolidationItemsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentConsolidationItemsDomain" xlink:label="SegmentConsolidationItemsDomain_2" xlink:title="SegmentConsolidationItemsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SegmentConsolidationItemsAxis" xlink:to="SegmentConsolidationItemsDomain_2" xlink:title="definition: SegmentConsolidationItemsAxis to SegmentConsolidationItemsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OperatingSegmentsMember" xlink:label="OperatingSegmentsMember" xlink:title="OperatingSegmentsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentConsolidationItemsDomain" xlink:to="OperatingSegmentsMember" xlink:title="definition: SegmentConsolidationItemsDomain to OperatingSegmentsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentsAxis" xlink:label="SegmentsAxis" xlink:title="SegmentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfOperatingSegmentsTable" xlink:to="SegmentsAxis" xlink:title="definition: DisclosureOfOperatingSegmentsTable to SegmentsAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentsDomain" xlink:label="SegmentsDomain" xlink:title="SegmentsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SegmentsAxis" xlink:to="SegmentsDomain" xlink:title="definition: SegmentsAxis to SegmentsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentsDomain" xlink:label="SegmentsDomain_2" xlink:title="SegmentsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SegmentsAxis" xlink:to="SegmentsDomain_2" xlink:title="definition: SegmentsAxis to SegmentsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PrecisionMedicineMember" xlink:label="PrecisionMedicineMember" xlink:title="PrecisionMedicineMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentsDomain" xlink:to="PrecisionMedicineMember" xlink:title="definition: SegmentsDomain to PrecisionMedicineMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TherapeuticsMember" xlink:label="TherapeuticsMember" xlink:title="TherapeuticsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentsDomain" xlink:to="TherapeuticsMember" xlink:title="definition: SegmentsDomain to TherapeuticsMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ManufacturingSolutionsMember" xlink:label="ManufacturingSolutionsMember" xlink:title="ManufacturingSolutionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentsDomain" xlink:to="ManufacturingSolutionsMember" xlink:title="definition: SegmentsDomain to ManufacturingSolutionsMember" order="3.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/SegmentReportingReconciliationOfSegmentAdjustedEbitdaAndGroupAdjustedEbitaDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:label="DisclosureOfOperatingSegmentsLineItems" xlink:title="DisclosureOfOperatingSegmentsLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ReconciliationOfTotalSegmentAdjustedEBITDAAndGroupAdjustedEBITAToProfitLossBeforeIncomeTaxAbstract" xlink:label="ReconciliationOfTotalSegmentAdjustedEBITDAAndGroupAdjustedEBITAToProfitLossBeforeIncomeTaxAbstract" xlink:title="ReconciliationOfTotalSegmentAdjustedEBITDAAndGroupAdjustedEBITAToProfitLossBeforeIncomeTaxAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="ReconciliationOfTotalSegmentAdjustedEBITDAAndGroupAdjustedEBITAToProfitLossBeforeIncomeTaxAbstract" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to ReconciliationOfTotalSegmentAdjustedEBITDAAndGroupAdjustedEBITAToProfitLossBeforeIncomeTaxAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_UnallocatedEmploymentCosts" xlink:label="UnallocatedEmploymentCosts" xlink:title="UnallocatedEmploymentCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="UnallocatedEmploymentCosts" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to UnallocatedEmploymentCosts" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AdjustedEarningsBeforeInterestTaxDepreciationAndAmortization" xlink:label="AdjustedEarningsBeforeInterestTaxDepreciationAndAmortization" xlink:title="AdjustedEarningsBeforeInterestTaxDepreciationAndAmortization" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="AdjustedEarningsBeforeInterestTaxDepreciationAndAmortization" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to AdjustedEarningsBeforeInterestTaxDepreciationAndAmortization" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_UnallocatedIncomeExpensesAndEliminationsAbstract" xlink:label="UnallocatedIncomeExpensesAndEliminationsAbstract" xlink:title="UnallocatedIncomeExpensesAndEliminationsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="UnallocatedIncomeExpensesAndEliminationsAbstract" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to UnallocatedIncomeExpensesAndEliminationsAbstract" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AdjustmentsForReconcileProfitLossAbstract" xlink:label="AdjustmentsForReconcileProfitLossAbstract" xlink:title="AdjustmentsForReconcileProfitLossAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="AdjustmentsForReconcileProfitLossAbstract" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to AdjustmentsForReconcileProfitLossAbstract" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_UnallocatedIncomeEliminationsAndExpensesAbstract" xlink:label="UnallocatedIncomeEliminationsAndExpensesAbstract" xlink:title="UnallocatedIncomeEliminationsAndExpensesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="UnallocatedIncomeEliminationsAndExpensesAbstract" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to UnallocatedIncomeEliminationsAndExpensesAbstract" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_UnallocatedOtherGainsLosses" xlink:label="UnallocatedOtherGainsLosses" xlink:title="UnallocatedOtherGainsLosses" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="UnallocatedOtherGainsLosses" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to UnallocatedOtherGainsLosses" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinanceIncome" xlink:label="FinanceIncome" xlink:title="FinanceIncome" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="FinanceIncome" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to FinanceIncome" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinanceCosts" xlink:label="FinanceCosts" xlink:title="FinanceCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="FinanceCosts" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to FinanceCosts" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_UnallocatedDepreciationAndAmortisationExpense" xlink:label="UnallocatedDepreciationAndAmortisationExpense" xlink:title="UnallocatedDepreciationAndAmortisationExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="UnallocatedDepreciationAndAmortisationExpense" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to UnallocatedDepreciationAndAmortisationExpense" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProfitLossBeforeTax" xlink:label="ProfitLossBeforeTax" xlink:title="ProfitLossBeforeTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="ProfitLossBeforeTax" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to ProfitLossBeforeTax" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_UnallocatedGeneralAndAdministrationCost" xlink:label="UnallocatedGeneralAndAdministrationCost" xlink:title="UnallocatedGeneralAndAdministrationCost" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="UnallocatedGeneralAndAdministrationCost" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to UnallocatedGeneralAndAdministrationCost" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ListingCosts" xlink:label="ListingCosts" xlink:title="ListingCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="ListingCosts" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to ListingCosts" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AcquisitionrelatedCostsForTransactionRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombination" xlink:label="AcquisitionrelatedCostsForTransactionRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombination" xlink:title="AcquisitionrelatedCostsForTransactionRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombination" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="AcquisitionrelatedCostsForTransactionRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombination" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to AcquisitionrelatedCostsForTransactionRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombination" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_UnallocatedGeneralAndAdministrationCosts" xlink:label="UnallocatedGeneralAndAdministrationCosts" xlink:title="UnallocatedGeneralAndAdministrationCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="UnallocatedGeneralAndAdministrationCosts" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to UnallocatedGeneralAndAdministrationCosts" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOperatingSegmentsTable" xlink:label="DisclosureOfOperatingSegmentsTable" xlink:title="DisclosureOfOperatingSegmentsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="DisclosureOfOperatingSegmentsTable" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to DisclosureOfOperatingSegmentsTable" order="16.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentConsolidationItemsAxis" xlink:label="SegmentConsolidationItemsAxis" xlink:title="SegmentConsolidationItemsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfOperatingSegmentsTable" xlink:to="SegmentConsolidationItemsAxis" xlink:title="definition: DisclosureOfOperatingSegmentsTable to SegmentConsolidationItemsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentConsolidationItemsDomain" xlink:label="SegmentConsolidationItemsDomain" xlink:title="SegmentConsolidationItemsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SegmentConsolidationItemsAxis" xlink:to="SegmentConsolidationItemsDomain" xlink:title="definition: SegmentConsolidationItemsAxis to SegmentConsolidationItemsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentConsolidationItemsDomain" xlink:label="SegmentConsolidationItemsDomain_2" xlink:title="SegmentConsolidationItemsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SegmentConsolidationItemsAxis" xlink:to="SegmentConsolidationItemsDomain_2" xlink:title="definition: SegmentConsolidationItemsAxis to SegmentConsolidationItemsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OperatingSegmentsMember" xlink:label="OperatingSegmentsMember" xlink:title="OperatingSegmentsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentConsolidationItemsDomain" xlink:to="OperatingSegmentsMember" xlink:title="definition: SegmentConsolidationItemsDomain to OperatingSegmentsMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/SegmentReportingOperatingSegmentAssetsAndLiabilitiesDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:label="DisclosureOfOperatingSegmentsLineItems" xlink:title="DisclosureOfOperatingSegmentsLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_OperatingSegmentAssetsAndLiabilitiesAbstract" xlink:label="OperatingSegmentAssetsAndLiabilitiesAbstract" xlink:title="OperatingSegmentAssetsAndLiabilitiesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="OperatingSegmentAssetsAndLiabilitiesAbstract" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to OperatingSegmentAssetsAndLiabilitiesAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashAndCashEquivalents" xlink:label="CashAndCashEquivalents" xlink:title="CashAndCashEquivalents" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="CashAndCashEquivalents" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to CashAndCashEquivalents" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncurrentFinancialAssets" xlink:label="NoncurrentFinancialAssets" xlink:title="NoncurrentFinancialAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="NoncurrentFinancialAssets" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to NoncurrentFinancialAssets" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PropertyPlantAndEquipment" xlink:label="PropertyPlantAndEquipment" xlink:title="PropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="PropertyPlantAndEquipment" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to PropertyPlantAndEquipment" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncurrentPortionOfNoncurrentBondsIssued" xlink:label="NoncurrentPortionOfNoncurrentBondsIssued" xlink:title="NoncurrentPortionOfNoncurrentBondsIssued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="NoncurrentPortionOfNoncurrentBondsIssued" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to NoncurrentPortionOfNoncurrentBondsIssued" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Assets" xlink:label="Assets" xlink:title="Assets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="Assets" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to Assets" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Liabilities" xlink:label="Liabilities" xlink:title="Liabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="Liabilities" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to Liabilities" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AdditionsToNoncurrentAssets" xlink:label="AdditionsToNoncurrentAssets" xlink:title="AdditionsToNoncurrentAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="AdditionsToNoncurrentAssets" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to AdditionsToNoncurrentAssets" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOperatingSegmentsTable" xlink:label="DisclosureOfOperatingSegmentsTable" xlink:title="DisclosureOfOperatingSegmentsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="DisclosureOfOperatingSegmentsTable" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to DisclosureOfOperatingSegmentsTable" order="9.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentConsolidationItemsAxis" xlink:label="SegmentConsolidationItemsAxis" xlink:title="SegmentConsolidationItemsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfOperatingSegmentsTable" xlink:to="SegmentConsolidationItemsAxis" xlink:title="definition: DisclosureOfOperatingSegmentsTable to SegmentConsolidationItemsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentConsolidationItemsDomain" xlink:label="SegmentConsolidationItemsDomain" xlink:title="SegmentConsolidationItemsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SegmentConsolidationItemsAxis" xlink:to="SegmentConsolidationItemsDomain" xlink:title="definition: SegmentConsolidationItemsAxis to SegmentConsolidationItemsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentConsolidationItemsDomain" xlink:label="SegmentConsolidationItemsDomain_2" xlink:title="SegmentConsolidationItemsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SegmentConsolidationItemsAxis" xlink:to="SegmentConsolidationItemsDomain_2" xlink:title="definition: SegmentConsolidationItemsAxis to SegmentConsolidationItemsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OperatingSegmentsMember" xlink:label="OperatingSegmentsMember" xlink:title="OperatingSegmentsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentConsolidationItemsDomain" xlink:to="OperatingSegmentsMember" xlink:title="definition: SegmentConsolidationItemsDomain to OperatingSegmentsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UnallocatedAmountsMember" xlink:label="UnallocatedAmountsMember" xlink:title="UnallocatedAmountsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentConsolidationItemsDomain" xlink:to="UnallocatedAmountsMember" xlink:title="definition: SegmentConsolidationItemsDomain to UnallocatedAmountsMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentsAxis" xlink:label="SegmentsAxis" xlink:title="SegmentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfOperatingSegmentsTable" xlink:to="SegmentsAxis" xlink:title="definition: DisclosureOfOperatingSegmentsTable to SegmentsAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentsDomain" xlink:label="SegmentsDomain" xlink:title="SegmentsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SegmentsAxis" xlink:to="SegmentsDomain" xlink:title="definition: SegmentsAxis to SegmentsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentsDomain" xlink:label="SegmentsDomain_2" xlink:title="SegmentsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SegmentsAxis" xlink:to="SegmentsDomain_2" xlink:title="definition: SegmentsAxis to SegmentsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PrecisionMedicineMember" xlink:label="PrecisionMedicineMember" xlink:title="PrecisionMedicineMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentsDomain" xlink:to="PrecisionMedicineMember" xlink:title="definition: SegmentsDomain to PrecisionMedicineMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TherapeuticsMember" xlink:label="TherapeuticsMember" xlink:title="TherapeuticsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentsDomain" xlink:to="TherapeuticsMember" xlink:title="definition: SegmentsDomain to TherapeuticsMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ManufacturingSolutionsMember" xlink:label="ManufacturingSolutionsMember" xlink:title="ManufacturingSolutionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentsDomain" xlink:to="ManufacturingSolutionsMember" xlink:title="definition: SegmentsDomain to ManufacturingSolutionsMember" order="3.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/SegmentReportingGeographicalInformationDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOperatingSegmentsLineItems" xlink:label="DisclosureOfOperatingSegmentsLineItems" xlink:title="DisclosureOfOperatingSegmentsLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GeographicalInformationAbstract" xlink:label="GeographicalInformationAbstract" xlink:title="GeographicalInformationAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="GeographicalInformationAbstract" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to GeographicalInformationAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RevenueFromContractsWithCustomers" xlink:label="RevenueFromContractsWithCustomers" xlink:title="RevenueFromContractsWithCustomers" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="RevenueFromContractsWithCustomers" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to RevenueFromContractsWithCustomers" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_NonCurrentAssetsByLocationOfAsset" xlink:label="NonCurrentAssetsByLocationOfAsset" xlink:title="NonCurrentAssetsByLocationOfAsset" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="NonCurrentAssetsByLocationOfAsset" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to NonCurrentAssetsByLocationOfAsset" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOperatingSegmentsTable" xlink:label="DisclosureOfOperatingSegmentsTable" xlink:title="DisclosureOfOperatingSegmentsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfOperatingSegmentsLineItems" xlink:to="DisclosureOfOperatingSegmentsTable" xlink:title="definition: DisclosureOfOperatingSegmentsLineItems to DisclosureOfOperatingSegmentsTable" order="4.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasAxis" xlink:label="GeographicalAreasAxis" xlink:title="GeographicalAreasAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfOperatingSegmentsTable" xlink:to="GeographicalAreasAxis" xlink:title="definition: DisclosureOfOperatingSegmentsTable to GeographicalAreasAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasDomain" xlink:label="GeographicalAreasDomain" xlink:title="GeographicalAreasDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="GeographicalAreasAxis" xlink:to="GeographicalAreasDomain" xlink:title="definition: GeographicalAreasAxis to GeographicalAreasDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasDomain" xlink:label="GeographicalAreasDomain_2" xlink:title="GeographicalAreasDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="GeographicalAreasAxis" xlink:to="GeographicalAreasDomain_2" xlink:title="definition: GeographicalAreasAxis to GeographicalAreasDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_AU" xlink:label="AU" xlink:title="AU" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GeographicalAreasDomain" xlink:to="AU" xlink:title="definition: GeographicalAreasDomain to AU" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_BE" xlink:label="BE" xlink:title="BE" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GeographicalAreasDomain" xlink:to="BE" xlink:title="definition: GeographicalAreasDomain to BE" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_CA" xlink:label="CA" xlink:title="CA" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GeographicalAreasDomain" xlink:to="CA" xlink:title="definition: GeographicalAreasDomain to CA" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_CN" xlink:label="CN" xlink:title="CN" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GeographicalAreasDomain" xlink:to="CN" xlink:title="definition: GeographicalAreasDomain to CN" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_GB" xlink:label="GB" xlink:title="GB" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GeographicalAreasDomain" xlink:to="GB" xlink:title="definition: GeographicalAreasDomain to GB" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_US" xlink:label="US" xlink:title="US" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GeographicalAreasDomain" xlink:to="US" xlink:title="definition: GeographicalAreasDomain to US" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ForeignCountriesMember" xlink:label="ForeignCountriesMember" xlink:title="ForeignCountriesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GeographicalAreasDomain" xlink:to="ForeignCountriesMember" xlink:title="definition: GeographicalAreasDomain to ForeignCountriesMember" order="7.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/RevenueFromContractsWithCustomersDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:label="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:title="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RevenueAbstract" xlink:label="RevenueAbstract" xlink:title="RevenueAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:to="RevenueAbstract" xlink:title="definition: DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems to RevenueAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RevenueFromSaleOfGoods" xlink:label="RevenueFromSaleOfGoods" xlink:title="RevenueFromSaleOfGoods" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:to="RevenueFromSaleOfGoods" xlink:title="definition: DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems to RevenueFromSaleOfGoods" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RevenueFromRoyalties" xlink:label="RevenueFromRoyalties" xlink:title="RevenueFromRoyalties" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:to="RevenueFromRoyalties" xlink:title="definition: DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems to RevenueFromRoyalties" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_RevenueFromProvisionOfServices" xlink:label="RevenueFromProvisionOfServices" xlink:title="RevenueFromProvisionOfServices" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:to="RevenueFromProvisionOfServices" xlink:title="definition: DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems to RevenueFromProvisionOfServices" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_LicensesOfIntellectualProperty" xlink:label="LicensesOfIntellectualProperty" xlink:title="LicensesOfIntellectualProperty" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:to="LicensesOfIntellectualProperty" xlink:title="definition: DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems to LicensesOfIntellectualProperty" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ResearchAndDevelopmentServices" xlink:label="ResearchAndDevelopmentServices" xlink:title="ResearchAndDevelopmentServices" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:to="ResearchAndDevelopmentServices" xlink:title="definition: DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems to ResearchAndDevelopmentServices" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Revenue" xlink:label="Revenue" xlink:title="Revenue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:to="Revenue" xlink:title="definition: DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems to Revenue" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable" xlink:label="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable" xlink:title="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:to="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable" xlink:title="definition: DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems to DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable" order="8.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TimingOfTransferOfGoodsOrServicesAxis" xlink:label="TimingOfTransferOfGoodsOrServicesAxis" xlink:title="TimingOfTransferOfGoodsOrServicesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable" xlink:to="TimingOfTransferOfGoodsOrServicesAxis" xlink:title="definition: DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable to TimingOfTransferOfGoodsOrServicesAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TimingOfTransferOfGoodsOrServicesDomain" xlink:label="TimingOfTransferOfGoodsOrServicesDomain" xlink:title="TimingOfTransferOfGoodsOrServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TimingOfTransferOfGoodsOrServicesAxis" xlink:to="TimingOfTransferOfGoodsOrServicesDomain" xlink:title="definition: TimingOfTransferOfGoodsOrServicesAxis to TimingOfTransferOfGoodsOrServicesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TimingOfTransferOfGoodsOrServicesDomain" xlink:label="TimingOfTransferOfGoodsOrServicesDomain_2" xlink:title="TimingOfTransferOfGoodsOrServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TimingOfTransferOfGoodsOrServicesAxis" xlink:to="TimingOfTransferOfGoodsOrServicesDomain_2" xlink:title="definition: TimingOfTransferOfGoodsOrServicesAxis to TimingOfTransferOfGoodsOrServicesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GoodsOrServicesTransferredAtPointInTimeMember" xlink:label="GoodsOrServicesTransferredAtPointInTimeMember" xlink:title="GoodsOrServicesTransferredAtPointInTimeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TimingOfTransferOfGoodsOrServicesDomain" xlink:to="GoodsOrServicesTransferredAtPointInTimeMember" xlink:title="definition: TimingOfTransferOfGoodsOrServicesDomain to GoodsOrServicesTransferredAtPointInTimeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GoodsOrServicesTransferredOverTimeMember" xlink:label="GoodsOrServicesTransferredOverTimeMember" xlink:title="GoodsOrServicesTransferredOverTimeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TimingOfTransferOfGoodsOrServicesDomain" xlink:to="GoodsOrServicesTransferredOverTimeMember" xlink:title="definition: TimingOfTransferOfGoodsOrServicesDomain to GoodsOrServicesTransferredOverTimeMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProductsAndServicesAxis" xlink:label="ProductsAndServicesAxis" xlink:title="ProductsAndServicesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable" xlink:to="ProductsAndServicesAxis" xlink:title="definition: DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable to ProductsAndServicesAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProductsAndServicesDomain" xlink:label="ProductsAndServicesDomain" xlink:title="ProductsAndServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ProductsAndServicesAxis" xlink:to="ProductsAndServicesDomain" xlink:title="definition: ProductsAndServicesAxis to ProductsAndServicesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProductsAndServicesDomain" xlink:label="ProductsAndServicesDomain_2" xlink:title="ProductsAndServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ProductsAndServicesAxis" xlink:to="ProductsAndServicesDomain_2" xlink:title="definition: ProductsAndServicesAxis to ProductsAndServicesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PrecisionMedicineMember" xlink:label="PrecisionMedicineMember" xlink:title="PrecisionMedicineMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="PrecisionMedicineMember" xlink:title="definition: ProductsAndServicesDomain to PrecisionMedicineMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ManufacturingSolutionsMember" xlink:label="ManufacturingSolutionsMember" xlink:title="ManufacturingSolutionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="ManufacturingSolutionsMember" xlink:title="definition: ProductsAndServicesDomain to ManufacturingSolutionsMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TherapeuticsMember" xlink:label="TherapeuticsMember" xlink:title="TherapeuticsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="TherapeuticsMember" xlink:title="definition: ProductsAndServicesDomain to TherapeuticsMember" order="3.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ResearchAndDevelopmentCostsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfProductsAndServicesLineItems" xlink:label="DisclosureOfProductsAndServicesLineItems" xlink:title="DisclosureOfProductsAndServicesLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfProductsAndServicesAbstract" xlink:label="DisclosureOfProductsAndServicesAbstract" xlink:title="DisclosureOfProductsAndServicesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfProductsAndServicesLineItems" xlink:to="DisclosureOfProductsAndServicesAbstract" xlink:title="definition: DisclosureOfProductsAndServicesLineItems to DisclosureOfProductsAndServicesAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ResearchAndDevelopmentExpense" xlink:label="ResearchAndDevelopmentExpense" xlink:title="ResearchAndDevelopmentExpense" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfProductsAndServicesLineItems" xlink:to="ResearchAndDevelopmentExpense" xlink:title="definition: DisclosureOfProductsAndServicesLineItems to ResearchAndDevelopmentExpense" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfProductsAndServicesTable" xlink:label="DisclosureOfProductsAndServicesTable" xlink:title="DisclosureOfProductsAndServicesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfProductsAndServicesLineItems" xlink:to="DisclosureOfProductsAndServicesTable" xlink:title="definition: DisclosureOfProductsAndServicesLineItems to DisclosureOfProductsAndServicesTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentsAxis" xlink:label="SegmentsAxis" xlink:title="SegmentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfProductsAndServicesTable" xlink:to="SegmentsAxis" xlink:title="definition: DisclosureOfProductsAndServicesTable to SegmentsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentsDomain" xlink:label="SegmentsDomain" xlink:title="SegmentsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SegmentsAxis" xlink:to="SegmentsDomain" xlink:title="definition: SegmentsAxis to SegmentsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SegmentsDomain" xlink:label="SegmentsDomain_2" xlink:title="SegmentsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SegmentsAxis" xlink:to="SegmentsDomain_2" xlink:title="definition: SegmentsAxis to SegmentsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TherapeuticsMember" xlink:label="TherapeuticsMember" xlink:title="TherapeuticsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentsDomain" xlink:to="TherapeuticsMember" xlink:title="definition: SegmentsDomain to TherapeuticsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PrecisionMedicineMember" xlink:label="PrecisionMedicineMember" xlink:title="PrecisionMedicineMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentsDomain" xlink:to="PrecisionMedicineMember" xlink:title="definition: SegmentsDomain to PrecisionMedicineMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ManufacturingSolutionsMember" xlink:label="ManufacturingSolutionsMember" xlink:title="ManufacturingSolutionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SegmentsDomain" xlink:to="ManufacturingSolutionsMember" xlink:title="definition: SegmentsDomain to ManufacturingSolutionsMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProductsAndServicesAxis" xlink:label="ProductsAndServicesAxis" xlink:title="ProductsAndServicesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfProductsAndServicesTable" xlink:to="ProductsAndServicesAxis" xlink:title="definition: DisclosureOfProductsAndServicesTable to ProductsAndServicesAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProductsAndServicesDomain" xlink:label="ProductsAndServicesDomain" xlink:title="ProductsAndServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ProductsAndServicesAxis" xlink:to="ProductsAndServicesDomain" xlink:title="definition: ProductsAndServicesAxis to ProductsAndServicesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProductsAndServicesDomain" xlink:label="ProductsAndServicesDomain_2" xlink:title="ProductsAndServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ProductsAndServicesAxis" xlink:to="ProductsAndServicesDomain_2" xlink:title="definition: ProductsAndServicesAxis to ProductsAndServicesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ProductDevelopmentMember" xlink:label="ProductDevelopmentMember" xlink:title="ProductDevelopmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="ProductDevelopmentMember" xlink:title="definition: ProductsAndServicesDomain to ProductDevelopmentMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TLX591Member" xlink:label="TLX591Member" xlink:title="TLX591Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductDevelopmentMember" xlink:to="TLX591Member" xlink:title="definition: ProductDevelopmentMember to TLX591Member" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TLX250AndTLX101Member" xlink:label="TLX250AndTLX101Member" xlink:title="TLX250AndTLX101Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductDevelopmentMember" xlink:to="TLX250AndTLX101Member" xlink:title="definition: ProductDevelopmentMember to TLX250AndTLX101Member" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TLX66AndTLX300Member" xlink:label="TLX66AndTLX300Member" xlink:title="TLX66AndTLX300Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductDevelopmentMember" xlink:to="TLX66AndTLX300Member" xlink:title="definition: ProductDevelopmentMember to TLX66AndTLX300Member" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IlluccixTLX591CDxMember" xlink:label="IlluccixTLX591CDxMember" xlink:title="IlluccixTLX591CDxMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductDevelopmentMember" xlink:to="IlluccixTLX591CDxMember" xlink:title="definition: ProductDevelopmentMember to IlluccixTLX591CDxMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PixclaraZircaixGozelixMember" xlink:label="PixclaraZircaixGozelixMember" xlink:title="PixclaraZircaixGozelixMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductDevelopmentMember" xlink:to="PixclaraZircaixGozelixMember" xlink:title="definition: ProductDevelopmentMember to PixclaraZircaixGozelixMember" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PreClinicalResearchAndInnovationMember" xlink:label="PreClinicalResearchAndInnovationMember" xlink:title="PreClinicalResearchAndInnovationMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductDevelopmentMember" xlink:to="PreClinicalResearchAndInnovationMember" xlink:title="definition: ProductDevelopmentMember to PreClinicalResearchAndInnovationMember" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_OtherResearchAndDevelopmentProjectsMember" xlink:label="OtherResearchAndDevelopmentProjectsMember" xlink:title="OtherResearchAndDevelopmentProjectsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductDevelopmentMember" xlink:to="OtherResearchAndDevelopmentProjectsMember" xlink:title="definition: ProductDevelopmentMember to OtherResearchAndDevelopmentProjectsMember" order="7.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/GeneralAndAdministrationCostsDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EmploymentCostsDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/DepreciationAndAmortizationDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/OtherGainsLossesNetDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/FinanceCostsDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/IncomeTaxExpenseBenefitSummaryDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/IncomeTaxExpenseBenefitNumericalReconciliationOfPrimaFacieTaxPayableToIncomeTaxExpenseBenefitDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EarningsPerShareDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_EarningsPerShareLineItems" xlink:label="EarningsPerShareLineItems" xlink:title="EarningsPerShareLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BasicEarningsPerShareAbstract" xlink:label="BasicEarningsPerShareAbstract" xlink:title="BasicEarningsPerShareAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarningsPerShareLineItems" xlink:to="BasicEarningsPerShareAbstract" xlink:title="definition: EarningsPerShareLineItems to BasicEarningsPerShareAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DilutedEarningsPerShareAbstract" xlink:label="DilutedEarningsPerShareAbstract" xlink:title="DilutedEarningsPerShareAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarningsPerShareLineItems" xlink:to="DilutedEarningsPerShareAbstract" xlink:title="definition: EarningsPerShareLineItems to DilutedEarningsPerShareAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_WeightedAverageSharesAndAdjustedWeightedAverageSharesAbstract" xlink:label="WeightedAverageSharesAndAdjustedWeightedAverageSharesAbstract" xlink:title="WeightedAverageSharesAndAdjustedWeightedAverageSharesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarningsPerShareLineItems" xlink:to="WeightedAverageSharesAndAdjustedWeightedAverageSharesAbstract" xlink:title="definition: EarningsPerShareLineItems to WeightedAverageSharesAndAdjustedWeightedAverageSharesAbstract" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfPotentialOrdinarySharesThatAreAntidilutiveInPeriodPresented" xlink:label="NumberOfPotentialOrdinarySharesThatAreAntidilutiveInPeriodPresented" xlink:title="NumberOfPotentialOrdinarySharesThatAreAntidilutiveInPeriodPresented" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarningsPerShareLineItems" xlink:to="NumberOfPotentialOrdinarySharesThatAreAntidilutiveInPeriodPresented" xlink:title="definition: EarningsPerShareLineItems to NumberOfPotentialOrdinarySharesThatAreAntidilutiveInPeriodPresented" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_WeightedAverageShares" xlink:label="WeightedAverageShares" xlink:title="WeightedAverageShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarningsPerShareLineItems" xlink:to="WeightedAverageShares" xlink:title="definition: EarningsPerShareLineItems to WeightedAverageShares" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AdjustedWeightedAverageShares" xlink:label="AdjustedWeightedAverageShares" xlink:title="AdjustedWeightedAverageShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarningsPerShareLineItems" xlink:to="AdjustedWeightedAverageShares" xlink:title="definition: EarningsPerShareLineItems to AdjustedWeightedAverageShares" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DilutedEarningsLossPerShareFromContinuingOperations" xlink:label="DilutedEarningsLossPerShareFromContinuingOperations" xlink:title="DilutedEarningsLossPerShareFromContinuingOperations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarningsPerShareLineItems" xlink:to="DilutedEarningsLossPerShareFromContinuingOperations" xlink:title="definition: EarningsPerShareLineItems to DilutedEarningsLossPerShareFromContinuingOperations" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DilutedEarningsLossPerShare" xlink:label="DilutedEarningsLossPerShare" xlink:title="DilutedEarningsLossPerShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarningsPerShareLineItems" xlink:to="DilutedEarningsLossPerShare" xlink:title="definition: EarningsPerShareLineItems to DilutedEarningsLossPerShare" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BasicEarningsLossPerShareFromContinuingOperations" xlink:label="BasicEarningsLossPerShareFromContinuingOperations" xlink:title="BasicEarningsLossPerShareFromContinuingOperations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarningsPerShareLineItems" xlink:to="BasicEarningsLossPerShareFromContinuingOperations" xlink:title="definition: EarningsPerShareLineItems to BasicEarningsLossPerShareFromContinuingOperations" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BasicEarningsLossPerShare" xlink:label="BasicEarningsLossPerShare" xlink:title="BasicEarningsLossPerShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EarningsPerShareLineItems" xlink:to="BasicEarningsLossPerShare" xlink:title="definition: EarningsPerShareLineItems to BasicEarningsLossPerShare" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_EarningsPerShareTable" xlink:label="EarningsPerShareTable" xlink:title="EarningsPerShareTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="EarningsPerShareLineItems" xlink:to="EarningsPerShareTable" xlink:title="definition: EarningsPerShareLineItems to EarningsPerShareTable" order="11.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfAntidilutiveInstrumentsAxis" xlink:label="TypesOfAntidilutiveInstrumentsAxis" xlink:title="TypesOfAntidilutiveInstrumentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="EarningsPerShareTable" xlink:to="TypesOfAntidilutiveInstrumentsAxis" xlink:title="definition: EarningsPerShareTable to TypesOfAntidilutiveInstrumentsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfAntidilutiveInstrumentsDomain" xlink:label="TypesOfAntidilutiveInstrumentsDomain" xlink:title="TypesOfAntidilutiveInstrumentsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TypesOfAntidilutiveInstrumentsAxis" xlink:to="TypesOfAntidilutiveInstrumentsDomain" xlink:title="definition: TypesOfAntidilutiveInstrumentsAxis to TypesOfAntidilutiveInstrumentsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfAntidilutiveInstrumentsDomain" xlink:label="TypesOfAntidilutiveInstrumentsDomain_2" xlink:title="TypesOfAntidilutiveInstrumentsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TypesOfAntidilutiveInstrumentsAxis" xlink:to="TypesOfAntidilutiveInstrumentsDomain_2" xlink:title="definition: TypesOfAntidilutiveInstrumentsAxis to TypesOfAntidilutiveInstrumentsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ShareOptionsMember" xlink:label="ShareOptionsMember" xlink:title="ShareOptionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TypesOfAntidilutiveInstrumentsDomain" xlink:to="ShareOptionsMember" xlink:title="definition: TypesOfAntidilutiveInstrumentsDomain to ShareOptionsMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/TradeAndOtherReceivablesDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/InventoriesDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/OtherCurrentAssetsDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/FinancialAssetsSummaryDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfSignificantInvestmentsInAssociatesLineItems" xlink:label="DisclosureOfSignificantInvestmentsInAssociatesLineItems" xlink:title="DisclosureOfSignificantInvestmentsInAssociatesLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfFinancialAssetsAbstract" xlink:label="DisclosureOfFinancialAssetsAbstract" xlink:title="DisclosureOfFinancialAssetsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfSignificantInvestmentsInAssociatesLineItems" xlink:to="DisclosureOfFinancialAssetsAbstract" xlink:title="definition: DisclosureOfSignificantInvestmentsInAssociatesLineItems to DisclosureOfFinancialAssetsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncurrentRestrictedCashAndCashEquivalents" xlink:label="NoncurrentRestrictedCashAndCashEquivalents" xlink:title="NoncurrentRestrictedCashAndCashEquivalents" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfSignificantInvestmentsInAssociatesLineItems" xlink:to="NoncurrentRestrictedCashAndCashEquivalents" xlink:title="definition: DisclosureOfSignificantInvestmentsInAssociatesLineItems to NoncurrentRestrictedCashAndCashEquivalents" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncurrentFinancialAssets" xlink:label="NoncurrentFinancialAssets" xlink:title="NoncurrentFinancialAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfSignificantInvestmentsInAssociatesLineItems" xlink:to="NoncurrentFinancialAssets" xlink:title="definition: DisclosureOfSignificantInvestmentsInAssociatesLineItems to NoncurrentFinancialAssets" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfSignificantInvestmentsInAssociatesTable" xlink:label="DisclosureOfSignificantInvestmentsInAssociatesTable" xlink:title="DisclosureOfSignificantInvestmentsInAssociatesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfSignificantInvestmentsInAssociatesLineItems" xlink:to="DisclosureOfSignificantInvestmentsInAssociatesTable" xlink:title="definition: DisclosureOfSignificantInvestmentsInAssociatesLineItems to DisclosureOfSignificantInvestmentsInAssociatesTable" order="4.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SignificantInvestmentsInAssociatesAxis" xlink:label="SignificantInvestmentsInAssociatesAxis" xlink:title="SignificantInvestmentsInAssociatesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfSignificantInvestmentsInAssociatesTable" xlink:to="SignificantInvestmentsInAssociatesAxis" xlink:title="definition: DisclosureOfSignificantInvestmentsInAssociatesTable to SignificantInvestmentsInAssociatesAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SignificantInvestmentsInAssociatesDomain" xlink:label="SignificantInvestmentsInAssociatesDomain" xlink:title="SignificantInvestmentsInAssociatesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SignificantInvestmentsInAssociatesAxis" xlink:to="SignificantInvestmentsInAssociatesDomain" xlink:title="definition: SignificantInvestmentsInAssociatesAxis to SignificantInvestmentsInAssociatesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SignificantInvestmentsInAssociatesDomain" xlink:label="SignificantInvestmentsInAssociatesDomain_2" xlink:title="SignificantInvestmentsInAssociatesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SignificantInvestmentsInAssociatesAxis" xlink:to="SignificantInvestmentsInAssociatesDomain_2" xlink:title="definition: SignificantInvestmentsInAssociatesAxis to SignificantInvestmentsInAssociatesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_MaunaKeaTechnologiesMember" xlink:label="MaunaKeaTechnologiesMember" xlink:title="MaunaKeaTechnologiesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInAssociatesDomain" xlink:to="MaunaKeaTechnologiesMember" xlink:title="definition: SignificantInvestmentsInAssociatesDomain to MaunaKeaTechnologiesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AtoncoSasMember" xlink:label="AtoncoSasMember" xlink:title="AtoncoSasMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInAssociatesDomain" xlink:to="AtoncoSasMember" xlink:title="definition: SignificantInvestmentsInAssociatesDomain to AtoncoSasMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_QSAMBiosciencesIncMember" xlink:label="QSAMBiosciencesIncMember" xlink:title="QSAMBiosciencesIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInAssociatesDomain" xlink:to="QSAMBiosciencesIncMember" xlink:title="definition: SignificantInvestmentsInAssociatesDomain to QSAMBiosciencesIncMember" order="3.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/FinancialAssetsAdditionsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfSignificantInvestmentsInAssociatesLineItems" xlink:label="DisclosureOfSignificantInvestmentsInAssociatesLineItems" xlink:title="DisclosureOfSignificantInvestmentsInAssociatesLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfFinancialAssetsAbstract" xlink:label="DisclosureOfFinancialAssetsAbstract" xlink:title="DisclosureOfFinancialAssetsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfSignificantInvestmentsInAssociatesLineItems" xlink:to="DisclosureOfFinancialAssetsAbstract" xlink:title="definition: DisclosureOfSignificantInvestmentsInAssociatesLineItems to DisclosureOfFinancialAssetsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_NumberOfOrdinarySharesSubscribed" xlink:label="NumberOfOrdinarySharesSubscribed" xlink:title="NumberOfOrdinarySharesSubscribed" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfSignificantInvestmentsInAssociatesLineItems" xlink:to="NumberOfOrdinarySharesSubscribed" xlink:title="definition: DisclosureOfSignificantInvestmentsInAssociatesLineItems to NumberOfOrdinarySharesSubscribed" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_SharePricePerShare" xlink:label="SharePricePerShare" xlink:title="SharePricePerShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfSignificantInvestmentsInAssociatesLineItems" xlink:to="SharePricePerShare" xlink:title="definition: DisclosureOfSignificantInvestmentsInAssociatesLineItems to SharePricePerShare" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_SharesConvertedForTradeReceivables" xlink:label="SharesConvertedForTradeReceivables" xlink:title="SharesConvertedForTradeReceivables" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfSignificantInvestmentsInAssociatesLineItems" xlink:to="SharesConvertedForTradeReceivables" xlink:title="definition: DisclosureOfSignificantInvestmentsInAssociatesLineItems to SharesConvertedForTradeReceivables" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProportionOfOwnershipInterestInAssociate" xlink:label="ProportionOfOwnershipInterestInAssociate" xlink:title="ProportionOfOwnershipInterestInAssociate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfSignificantInvestmentsInAssociatesLineItems" xlink:to="ProportionOfOwnershipInterestInAssociate" xlink:title="definition: DisclosureOfSignificantInvestmentsInAssociatesLineItems to ProportionOfOwnershipInterestInAssociate" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProportionOfVotingPowerHeldInAssociate" xlink:label="ProportionOfVotingPowerHeldInAssociate" xlink:title="ProportionOfVotingPowerHeldInAssociate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfSignificantInvestmentsInAssociatesLineItems" xlink:to="ProportionOfVotingPowerHeldInAssociate" xlink:title="definition: DisclosureOfSignificantInvestmentsInAssociatesLineItems to ProportionOfVotingPowerHeldInAssociate" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherComprehensiveIncomeNetOfTaxGainsLossesFromInvestmentsInEquityInstruments" xlink:label="OtherComprehensiveIncomeNetOfTaxGainsLossesFromInvestmentsInEquityInstruments" xlink:title="OtherComprehensiveIncomeNetOfTaxGainsLossesFromInvestmentsInEquityInstruments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfSignificantInvestmentsInAssociatesLineItems" xlink:to="OtherComprehensiveIncomeNetOfTaxGainsLossesFromInvestmentsInEquityInstruments" xlink:title="definition: DisclosureOfSignificantInvestmentsInAssociatesLineItems to OtherComprehensiveIncomeNetOfTaxGainsLossesFromInvestmentsInEquityInstruments" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfSignificantInvestmentsInAssociatesTable" xlink:label="DisclosureOfSignificantInvestmentsInAssociatesTable" xlink:title="DisclosureOfSignificantInvestmentsInAssociatesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfSignificantInvestmentsInAssociatesLineItems" xlink:to="DisclosureOfSignificantInvestmentsInAssociatesTable" xlink:title="definition: DisclosureOfSignificantInvestmentsInAssociatesLineItems to DisclosureOfSignificantInvestmentsInAssociatesTable" order="8.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SignificantInvestmentsInAssociatesAxis" xlink:label="SignificantInvestmentsInAssociatesAxis" xlink:title="SignificantInvestmentsInAssociatesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfSignificantInvestmentsInAssociatesTable" xlink:to="SignificantInvestmentsInAssociatesAxis" xlink:title="definition: DisclosureOfSignificantInvestmentsInAssociatesTable to SignificantInvestmentsInAssociatesAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SignificantInvestmentsInAssociatesDomain" xlink:label="SignificantInvestmentsInAssociatesDomain" xlink:title="SignificantInvestmentsInAssociatesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SignificantInvestmentsInAssociatesAxis" xlink:to="SignificantInvestmentsInAssociatesDomain" xlink:title="definition: SignificantInvestmentsInAssociatesAxis to SignificantInvestmentsInAssociatesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SignificantInvestmentsInAssociatesDomain" xlink:label="SignificantInvestmentsInAssociatesDomain_2" xlink:title="SignificantInvestmentsInAssociatesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SignificantInvestmentsInAssociatesAxis" xlink:to="SignificantInvestmentsInAssociatesDomain_2" xlink:title="definition: SignificantInvestmentsInAssociatesAxis to SignificantInvestmentsInAssociatesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AtoncoSasMember" xlink:label="AtoncoSasMember" xlink:title="AtoncoSasMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInAssociatesDomain" xlink:to="AtoncoSasMember" xlink:title="definition: SignificantInvestmentsInAssociatesDomain to AtoncoSasMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LevelsOfFairValueHierarchyAxis" xlink:label="LevelsOfFairValueHierarchyAxis" xlink:title="LevelsOfFairValueHierarchyAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfSignificantInvestmentsInAssociatesTable" xlink:to="LevelsOfFairValueHierarchyAxis" xlink:title="definition: DisclosureOfSignificantInvestmentsInAssociatesTable to LevelsOfFairValueHierarchyAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LevelsOfFairValueHierarchyDomain" xlink:label="LevelsOfFairValueHierarchyDomain" xlink:title="LevelsOfFairValueHierarchyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LevelsOfFairValueHierarchyAxis" xlink:to="LevelsOfFairValueHierarchyDomain" xlink:title="definition: LevelsOfFairValueHierarchyAxis to LevelsOfFairValueHierarchyDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LevelsOfFairValueHierarchyDomain" xlink:label="LevelsOfFairValueHierarchyDomain_2" xlink:title="LevelsOfFairValueHierarchyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LevelsOfFairValueHierarchyAxis" xlink:to="LevelsOfFairValueHierarchyDomain_2" xlink:title="definition: LevelsOfFairValueHierarchyAxis to LevelsOfFairValueHierarchyDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Level1OfFairValueHierarchyMember" xlink:label="Level1OfFairValueHierarchyMember" xlink:title="Level1OfFairValueHierarchyMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LevelsOfFairValueHierarchyDomain" xlink:to="Level1OfFairValueHierarchyMember" xlink:title="definition: LevelsOfFairValueHierarchyDomain to Level1OfFairValueHierarchyMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/DeferredTaxAssetsAndLiabilitiesDeferredTaxAssetsAndLiabilitiesDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:label="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:title="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DeferredTaxAssetsAbstract" xlink:label="DeferredTaxAssetsAbstract" xlink:title="DeferredTaxAssetsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="DeferredTaxAssetsAbstract" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems to DeferredTaxAssetsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DeferredTaxLiabilityAbstract" xlink:label="DeferredTaxLiabilityAbstract" xlink:title="DeferredTaxLiabilityAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="DeferredTaxLiabilityAbstract" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems to DeferredTaxLiabilityAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DeferredTaxLiabilitiesGross" xlink:label="DeferredTaxLiabilitiesGross" xlink:title="DeferredTaxLiabilitiesGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="DeferredTaxLiabilitiesGross" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems to DeferredTaxLiabilitiesGross" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DeferredTaxAssetsPursuantToSetOffProvisions" xlink:label="DeferredTaxAssetsPursuantToSetOffProvisions" xlink:title="DeferredTaxAssetsPursuantToSetOffProvisions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="DeferredTaxAssetsPursuantToSetOffProvisions" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems to DeferredTaxAssetsPursuantToSetOffProvisions" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DeferredTaxLiabilities" xlink:label="DeferredTaxLiabilities" xlink:title="DeferredTaxLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="DeferredTaxLiabilities" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems to DeferredTaxLiabilities" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DeferredTaxLiabilityOnAcquisition" xlink:label="DeferredTaxLiabilityOnAcquisition" xlink:title="DeferredTaxLiabilityOnAcquisition" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="DeferredTaxLiabilityOnAcquisition" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems to DeferredTaxLiabilityOnAcquisition" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DeferredTaxLiabilityDeferredTaxExpenseIncomeRecognizedInProfitOrLoss" xlink:label="DeferredTaxLiabilityDeferredTaxExpenseIncomeRecognizedInProfitOrLoss" xlink:title="DeferredTaxLiabilityDeferredTaxExpenseIncomeRecognizedInProfitOrLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="DeferredTaxLiabilityDeferredTaxExpenseIncomeRecognizedInProfitOrLoss" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems to DeferredTaxLiabilityDeferredTaxExpenseIncomeRecognizedInProfitOrLoss" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DeferredTaxAssetGross" xlink:label="DeferredTaxAssetGross" xlink:title="DeferredTaxAssetGross" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="DeferredTaxAssetGross" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems to DeferredTaxAssetGross" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DeferredTaxLiabilitiesPursuantToSetOffProvisions" xlink:label="DeferredTaxLiabilitiesPursuantToSetOffProvisions" xlink:title="DeferredTaxLiabilitiesPursuantToSetOffProvisions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="DeferredTaxLiabilitiesPursuantToSetOffProvisions" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems to DeferredTaxLiabilitiesPursuantToSetOffProvisions" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DeferredTaxExpenseIncomeRecognisedInProfitOrLoss" xlink:label="DeferredTaxExpenseIncomeRecognisedInProfitOrLoss" xlink:title="DeferredTaxExpenseIncomeRecognisedInProfitOrLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="DeferredTaxExpenseIncomeRecognisedInProfitOrLoss" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems to DeferredTaxExpenseIncomeRecognisedInProfitOrLoss" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DeferredTaxAssets" xlink:label="DeferredTaxAssets" xlink:title="DeferredTaxAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="DeferredTaxAssets" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems to DeferredTaxAssets" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" xlink:label="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" xlink:title="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems to DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" order="12.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" xlink:label="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" xlink:title="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" xlink:to="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable to TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:label="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:title="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" xlink:to="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:title="definition: TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis to TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:label="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain_2" xlink:title="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" xlink:to="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain_2" xlink:title="definition: TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis to TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UnusedTaxLossesMember" xlink:label="UnusedTaxLossesMember" xlink:title="UnusedTaxLossesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="UnusedTaxLossesMember" xlink:title="definition: TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain to UnusedTaxLossesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IntangibleAssetsMember" xlink:label="IntangibleAssetsMember" xlink:title="IntangibleAssetsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="IntangibleAssetsMember" xlink:title="definition: TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain to IntangibleAssetsMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_EmployeeBenefitObligationsMember" xlink:label="EmployeeBenefitObligationsMember" xlink:title="EmployeeBenefitObligationsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="EmployeeBenefitObligationsMember" xlink:title="definition: TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain to EmployeeBenefitObligationsMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LeaseLiabilitiesMember" xlink:label="LeaseLiabilitiesMember" xlink:title="LeaseLiabilitiesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="LeaseLiabilitiesMember" xlink:title="definition: TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain to LeaseLiabilitiesMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_InventoryMember" xlink:label="InventoryMember" xlink:title="InventoryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="InventoryMember" xlink:title="definition: TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain to InventoryMember" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherTemporaryDifferencesMember" xlink:label="OtherTemporaryDifferencesMember" xlink:title="OtherTemporaryDifferencesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="OtherTemporaryDifferencesMember" xlink:title="definition: TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain to OtherTemporaryDifferencesMember" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RightofuseAssetsMember" xlink:label="RightofuseAssetsMember" xlink:title="RightofuseAssetsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="RightofuseAssetsMember" xlink:title="definition: TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain to RightofuseAssetsMember" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UnrealisedForeignExchangeGainsLossesMember" xlink:label="UnrealisedForeignExchangeGainsLossesMember" xlink:title="UnrealisedForeignExchangeGainsLossesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="UnrealisedForeignExchangeGainsLossesMember" xlink:title="definition: TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain to UnrealisedForeignExchangeGainsLossesMember" order="8.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/DeferredTaxAssetsAndLiabilitiesUnrecognizedDeferredTaxAssetsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:label="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:title="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ReconciliationOfChangesInDeferredTaxLiabilityAssetAbstract" xlink:label="ReconciliationOfChangesInDeferredTaxLiabilityAssetAbstract" xlink:title="ReconciliationOfChangesInDeferredTaxLiabilityAssetAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="ReconciliationOfChangesInDeferredTaxLiabilityAssetAbstract" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems to ReconciliationOfChangesInDeferredTaxLiabilityAssetAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DeductibleTemporaryDifferencesForWhichNoDeferredTaxAssetIsRecognised" xlink:label="DeductibleTemporaryDifferencesForWhichNoDeferredTaxAssetIsRecognised" xlink:title="DeductibleTemporaryDifferencesForWhichNoDeferredTaxAssetIsRecognised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="DeductibleTemporaryDifferencesForWhichNoDeferredTaxAssetIsRecognised" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems to DeductibleTemporaryDifferencesForWhichNoDeferredTaxAssetIsRecognised" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" xlink:label="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" xlink:title="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems to DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" xlink:label="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" xlink:title="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" xlink:to="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable to TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:label="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:title="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" xlink:to="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:title="definition: TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis to TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:label="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain_2" xlink:title="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis" xlink:to="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain_2" xlink:title="definition: TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAxis to TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TemporaryDifferenceMember" xlink:label="TemporaryDifferenceMember" xlink:title="TemporaryDifferenceMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain" xlink:to="TemporaryDifferenceMember" xlink:title="definition: TemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsDomain to TemporaryDifferenceMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TaxLossesAndTaxCreditsMember" xlink:label="TaxLossesAndTaxCreditsMember" xlink:title="TaxLossesAndTaxCreditsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TemporaryDifferenceMember" xlink:to="TaxLossesAndTaxCreditsMember" xlink:title="definition: TemporaryDifferenceMember to TaxLossesAndTaxCreditsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ProvisionsMember" xlink:label="ProvisionsMember" xlink:title="ProvisionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TemporaryDifferenceMember" xlink:to="ProvisionsMember" xlink:title="definition: TemporaryDifferenceMember to ProvisionsMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_EmployeeBenefitObligationsMember" xlink:label="EmployeeBenefitObligationsMember" xlink:title="EmployeeBenefitObligationsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TemporaryDifferenceMember" xlink:to="EmployeeBenefitObligationsMember" xlink:title="definition: TemporaryDifferenceMember to EmployeeBenefitObligationsMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IntangibleAssetsMember" xlink:label="IntangibleAssetsMember" xlink:title="IntangibleAssetsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TemporaryDifferenceMember" xlink:to="IntangibleAssetsMember" xlink:title="definition: TemporaryDifferenceMember to IntangibleAssetsMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_InventoryMember" xlink:label="InventoryMember" xlink:title="InventoryMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TemporaryDifferenceMember" xlink:to="InventoryMember" xlink:title="definition: TemporaryDifferenceMember to InventoryMember" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LeaseLiabilitiesMember" xlink:label="LeaseLiabilitiesMember" xlink:title="LeaseLiabilitiesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TemporaryDifferenceMember" xlink:to="LeaseLiabilitiesMember" xlink:title="definition: TemporaryDifferenceMember to LeaseLiabilitiesMember" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ShareBasedPaymentsMember" xlink:label="ShareBasedPaymentsMember" xlink:title="ShareBasedPaymentsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TemporaryDifferenceMember" xlink:to="ShareBasedPaymentsMember" xlink:title="definition: TemporaryDifferenceMember to ShareBasedPaymentsMember" order="7.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/DeferredTaxAssetsAndLiabilitiesUnrecognizedTaxLossesDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:label="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:title="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAbstract" xlink:label="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAbstract" xlink:title="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAbstract" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems to DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UnusedTaxLossesForWhichNoDeferredTaxAssetRecognised" xlink:label="UnusedTaxLossesForWhichNoDeferredTaxAssetRecognised" xlink:title="UnusedTaxLossesForWhichNoDeferredTaxAssetRecognised" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="UnusedTaxLossesForWhichNoDeferredTaxAssetRecognised" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems to UnusedTaxLossesForWhichNoDeferredTaxAssetRecognised" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" xlink:label="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" xlink:title="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems" xlink:to="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsLineItems to DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasAxis" xlink:label="GeographicalAreasAxis" xlink:title="GeographicalAreasAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable" xlink:to="GeographicalAreasAxis" xlink:title="definition: DisclosureOfTemporaryDifferenceUnusedTaxLossesAndUnusedTaxCreditsTable to GeographicalAreasAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasDomain" xlink:label="GeographicalAreasDomain" xlink:title="GeographicalAreasDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="GeographicalAreasAxis" xlink:to="GeographicalAreasDomain" xlink:title="definition: GeographicalAreasAxis to GeographicalAreasDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasDomain" xlink:label="GeographicalAreasDomain_2" xlink:title="GeographicalAreasDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="GeographicalAreasAxis" xlink:to="GeographicalAreasDomain_2" xlink:title="definition: GeographicalAreasAxis to GeographicalAreasDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2024/country-2024.xsd#country_AU" xlink:label="AU" xlink:title="AU" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GeographicalAreasDomain" xlink:to="AU" xlink:title="definition: GeographicalAreasDomain to AU" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ForeignCountriesMember" xlink:label="ForeignCountriesMember" xlink:title="ForeignCountriesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GeographicalAreasDomain" xlink:to="ForeignCountriesMember" xlink:title="definition: GeographicalAreasDomain to ForeignCountriesMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/PropertyPlantAndEquipmentDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:label="DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:title="DisclosureOfPropertyPlantAndEquipmentLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ReconciliationOfChangesInPropertyPlantAndEquipmentAbstract" xlink:label="ReconciliationOfChangesInPropertyPlantAndEquipmentAbstract" xlink:title="ReconciliationOfChangesInPropertyPlantAndEquipmentAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="ReconciliationOfChangesInPropertyPlantAndEquipmentAbstract" xlink:title="definition: DisclosureOfPropertyPlantAndEquipmentLineItems to ReconciliationOfChangesInPropertyPlantAndEquipmentAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PropertyPlantAndEquipment" xlink:label="PropertyPlantAndEquipment" xlink:title="PropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipment" xlink:title="definition: DisclosureOfPropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipment" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AdditionsOtherThanThroughBusinessCombinationsPropertyPlantAndEquipment" xlink:label="AdditionsOtherThanThroughBusinessCombinationsPropertyPlantAndEquipment" xlink:title="AdditionsOtherThanThroughBusinessCombinationsPropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="AdditionsOtherThanThroughBusinessCombinationsPropertyPlantAndEquipment" xlink:title="definition: DisclosureOfPropertyPlantAndEquipmentLineItems to AdditionsOtherThanThroughBusinessCombinationsPropertyPlantAndEquipment" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AcquisitionsThroughBusinessCombinationsPropertyPlantAndEquipment" xlink:label="AcquisitionsThroughBusinessCombinationsPropertyPlantAndEquipment" xlink:title="AcquisitionsThroughBusinessCombinationsPropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="AcquisitionsThroughBusinessCombinationsPropertyPlantAndEquipment" xlink:title="definition: DisclosureOfPropertyPlantAndEquipmentLineItems to AcquisitionsThroughBusinessCombinationsPropertyPlantAndEquipment" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughTransfersPropertyPlantAndEquipment" xlink:label="IncreaseDecreaseThroughTransfersPropertyPlantAndEquipment" xlink:title="IncreaseDecreaseThroughTransfersPropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="IncreaseDecreaseThroughTransfersPropertyPlantAndEquipment" xlink:title="definition: DisclosureOfPropertyPlantAndEquipmentLineItems to IncreaseDecreaseThroughTransfersPropertyPlantAndEquipment" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ChangeInProvisionsPropertyPlantAndEquipment" xlink:label="ChangeInProvisionsPropertyPlantAndEquipment" xlink:title="ChangeInProvisionsPropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="ChangeInProvisionsPropertyPlantAndEquipment" xlink:title="definition: DisclosureOfPropertyPlantAndEquipmentLineItems to ChangeInProvisionsPropertyPlantAndEquipment" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DepreciationPropertyPlantAndEquipment" xlink:label="DepreciationPropertyPlantAndEquipment" xlink:title="DepreciationPropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="DepreciationPropertyPlantAndEquipment" xlink:title="definition: DisclosureOfPropertyPlantAndEquipmentLineItems to DepreciationPropertyPlantAndEquipment" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughNetExchangeDifferencesPropertyPlantAndEquipment" xlink:label="IncreaseDecreaseThroughNetExchangeDifferencesPropertyPlantAndEquipment" xlink:title="IncreaseDecreaseThroughNetExchangeDifferencesPropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="IncreaseDecreaseThroughNetExchangeDifferencesPropertyPlantAndEquipment" xlink:title="definition: DisclosureOfPropertyPlantAndEquipmentLineItems to IncreaseDecreaseThroughNetExchangeDifferencesPropertyPlantAndEquipment" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PropertyPlantAndEquipmentCost" xlink:label="PropertyPlantAndEquipmentCost" xlink:title="PropertyPlantAndEquipmentCost" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="PropertyPlantAndEquipmentCost" xlink:title="definition: DisclosureOfPropertyPlantAndEquipmentLineItems to PropertyPlantAndEquipmentCost" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AccumulatedDepreciationPropertyPlantAndEquipment" xlink:label="AccumulatedDepreciationPropertyPlantAndEquipment" xlink:title="AccumulatedDepreciationPropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="AccumulatedDepreciationPropertyPlantAndEquipment" xlink:title="definition: DisclosureOfPropertyPlantAndEquipmentLineItems to AccumulatedDepreciationPropertyPlantAndEquipment" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfPropertyPlantAndEquipmentTable" xlink:label="DisclosureOfPropertyPlantAndEquipmentTable" xlink:title="DisclosureOfPropertyPlantAndEquipmentTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfPropertyPlantAndEquipmentLineItems" xlink:to="DisclosureOfPropertyPlantAndEquipmentTable" xlink:title="definition: DisclosureOfPropertyPlantAndEquipmentLineItems to DisclosureOfPropertyPlantAndEquipmentTable" order="11.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentAxis" xlink:label="ClassesOfPropertyPlantAndEquipmentAxis" xlink:title="ClassesOfPropertyPlantAndEquipmentAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfPropertyPlantAndEquipmentTable" xlink:to="ClassesOfPropertyPlantAndEquipmentAxis" xlink:title="definition: DisclosureOfPropertyPlantAndEquipmentTable to ClassesOfPropertyPlantAndEquipmentAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:label="ClassesOfPropertyPlantAndEquipmentDomain" xlink:title="ClassesOfPropertyPlantAndEquipmentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ClassesOfPropertyPlantAndEquipmentAxis" xlink:to="ClassesOfPropertyPlantAndEquipmentDomain" xlink:title="definition: ClassesOfPropertyPlantAndEquipmentAxis to ClassesOfPropertyPlantAndEquipmentDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfPropertyPlantAndEquipmentDomain" xlink:label="ClassesOfPropertyPlantAndEquipmentDomain_2" xlink:title="ClassesOfPropertyPlantAndEquipmentDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassesOfPropertyPlantAndEquipmentAxis" xlink:to="ClassesOfPropertyPlantAndEquipmentDomain_2" xlink:title="definition: ClassesOfPropertyPlantAndEquipmentAxis to ClassesOfPropertyPlantAndEquipmentDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LandAndBuildingsMember" xlink:label="LandAndBuildingsMember" xlink:title="LandAndBuildingsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="LandAndBuildingsMember" xlink:title="definition: ClassesOfPropertyPlantAndEquipmentDomain to LandAndBuildingsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PropertyPlantAndEquipmentMember" xlink:label="PropertyPlantAndEquipmentMember" xlink:title="PropertyPlantAndEquipmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="PropertyPlantAndEquipmentMember" xlink:title="definition: ClassesOfPropertyPlantAndEquipmentDomain to PropertyPlantAndEquipmentMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FixturesAndFittingsMember" xlink:label="FixturesAndFittingsMember" xlink:title="FixturesAndFittingsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="FixturesAndFittingsMember" xlink:title="definition: ClassesOfPropertyPlantAndEquipmentDomain to FixturesAndFittingsMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LeaseholdImprovementsMember" xlink:label="LeaseholdImprovementsMember" xlink:title="LeaseholdImprovementsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="LeaseholdImprovementsMember" xlink:title="definition: ClassesOfPropertyPlantAndEquipmentDomain to LeaseholdImprovementsMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_LandAndBuildingsAndPlantAndEquipmentMember" xlink:label="LandAndBuildingsAndPlantAndEquipmentMember" xlink:title="LandAndBuildingsAndPlantAndEquipmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfPropertyPlantAndEquipmentDomain" xlink:to="LandAndBuildingsAndPlantAndEquipmentMember" xlink:title="definition: ClassesOfPropertyPlantAndEquipmentDomain to LandAndBuildingsAndPlantAndEquipmentMember" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasAxis" xlink:label="GeographicalAreasAxis" xlink:title="GeographicalAreasAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfPropertyPlantAndEquipmentTable" xlink:to="GeographicalAreasAxis" xlink:title="definition: DisclosureOfPropertyPlantAndEquipmentTable to GeographicalAreasAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasDomain" xlink:label="GeographicalAreasDomain" xlink:title="GeographicalAreasDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="GeographicalAreasAxis" xlink:to="GeographicalAreasDomain" xlink:title="definition: GeographicalAreasAxis to GeographicalAreasDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GeographicalAreasDomain" xlink:label="GeographicalAreasDomain_2" xlink:title="GeographicalAreasDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="GeographicalAreasAxis" xlink:to="GeographicalAreasDomain_2" xlink:title="definition: GeographicalAreasAxis to GeographicalAreasDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_BrusselsSouthMember" xlink:label="BrusselsSouthMember" xlink:title="BrusselsSouthMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="GeographicalAreasDomain" xlink:to="BrusselsSouthMember" xlink:title="definition: GeographicalAreasDomain to BrusselsSouthMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/RightofuseAssetsRightofuseAssetsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:label="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:title="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ReconciliationOfChangesInRightofuseAssetsAbstract" xlink:label="ReconciliationOfChangesInRightofuseAssetsAbstract" xlink:title="ReconciliationOfChangesInRightofuseAssetsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="ReconciliationOfChangesInRightofuseAssetsAbstract" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems to ReconciliationOfChangesInRightofuseAssetsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RightofuseAssets" xlink:label="RightofuseAssets" xlink:title="RightofuseAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="RightofuseAssets" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems to RightofuseAssets" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AdditionsToRightofuseAssets" xlink:label="AdditionsToRightofuseAssets" xlink:title="AdditionsToRightofuseAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="AdditionsToRightofuseAssets" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems to AdditionsToRightofuseAssets" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AcquisitionsThroughBusinessCombinationsRightofuseAssets" xlink:label="AcquisitionsThroughBusinessCombinationsRightofuseAssets" xlink:title="AcquisitionsThroughBusinessCombinationsRightofuseAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="AcquisitionsThroughBusinessCombinationsRightofuseAssets" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems to AcquisitionsThroughBusinessCombinationsRightofuseAssets" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ReclassificationsRightOfUseAsset" xlink:label="ReclassificationsRightOfUseAsset" xlink:title="ReclassificationsRightOfUseAsset" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="ReclassificationsRightOfUseAsset" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems to ReclassificationsRightOfUseAsset" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DepreciationRightofuseAssets" xlink:label="DepreciationRightofuseAssets" xlink:title="DepreciationRightofuseAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="DepreciationRightofuseAssets" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems to DepreciationRightofuseAssets" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughNetExchangeDifferencesRightofuseAssets" xlink:label="IncreaseDecreaseThroughNetExchangeDifferencesRightofuseAssets" xlink:title="IncreaseDecreaseThroughNetExchangeDifferencesRightofuseAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="IncreaseDecreaseThroughNetExchangeDifferencesRightofuseAssets" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems to IncreaseDecreaseThroughNetExchangeDifferencesRightofuseAssets" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_RightOfUseAssetNetBookAmount" xlink:label="RightOfUseAssetNetBookAmount" xlink:title="RightOfUseAssetNetBookAmount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="RightOfUseAssetNetBookAmount" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems to RightOfUseAssetNetBookAmount" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" xlink:label="DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" xlink:title="DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems to DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" order="9.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfAssetsAxis" xlink:label="ClassesOfAssetsAxis" xlink:title="ClassesOfAssetsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" xlink:to="ClassesOfAssetsAxis" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable to ClassesOfAssetsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfAssetsDomain" xlink:label="ClassesOfAssetsDomain" xlink:title="ClassesOfAssetsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ClassesOfAssetsAxis" xlink:to="ClassesOfAssetsDomain" xlink:title="definition: ClassesOfAssetsAxis to ClassesOfAssetsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfAssetsDomain" xlink:label="ClassesOfAssetsDomain_2" xlink:title="ClassesOfAssetsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassesOfAssetsAxis" xlink:to="ClassesOfAssetsDomain_2" xlink:title="definition: ClassesOfAssetsAxis to ClassesOfAssetsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PropertiesMember" xlink:label="PropertiesMember" xlink:title="PropertiesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfAssetsDomain" xlink:to="PropertiesMember" xlink:title="definition: ClassesOfAssetsDomain to PropertiesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MotorVehiclesMember" xlink:label="MotorVehiclesMember" xlink:title="MotorVehiclesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfAssetsDomain" xlink:to="MotorVehiclesMember" xlink:title="definition: ClassesOfAssetsDomain to MotorVehiclesMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis" xlink:label="CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis" xlink:title="CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" xlink:to="CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable to CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CarryingAmountMember" xlink:label="CarryingAmountMember" xlink:title="CarryingAmountMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis" xlink:to="CarryingAmountMember" xlink:title="definition: CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis to CarryingAmountMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CarryingAmountMember" xlink:label="CarryingAmountMember_2" xlink:title="CarryingAmountMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis" xlink:to="CarryingAmountMember_2" xlink:title="definition: CarryingAmountAccumulatedDepreciationAmortisationAndImpairmentAndGrossCarryingAmountAxis to CarryingAmountMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GrossCarryingAmountMember" xlink:label="GrossCarryingAmountMember" xlink:title="GrossCarryingAmountMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CarryingAmountMember" xlink:to="GrossCarryingAmountMember" xlink:title="definition: CarryingAmountMember to GrossCarryingAmountMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AccumulatedDepreciationAmortisationAndImpairmentMember" xlink:label="AccumulatedDepreciationAmortisationAndImpairmentMember" xlink:title="AccumulatedDepreciationAmortisationAndImpairmentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CarryingAmountMember" xlink:to="AccumulatedDepreciationAmortisationAndImpairmentMember" xlink:title="definition: CarryingAmountMember to AccumulatedDepreciationAmortisationAndImpairmentMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AccumulatedDepreciationAndAmortisationMember" xlink:label="AccumulatedDepreciationAndAmortisationMember" xlink:title="AccumulatedDepreciationAndAmortisationMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AccumulatedDepreciationAmortisationAndImpairmentMember" xlink:to="AccumulatedDepreciationAndAmortisationMember" xlink:title="definition: AccumulatedDepreciationAmortisationAndImpairmentMember to AccumulatedDepreciationAndAmortisationMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/RightofuseAssetsDepreciationChargeOnRightofuseAssetsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:label="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:title="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ReconciliationOfChangesInRightofuseAssetsAbstract" xlink:label="ReconciliationOfChangesInRightofuseAssetsAbstract" xlink:title="ReconciliationOfChangesInRightofuseAssetsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="ReconciliationOfChangesInRightofuseAssetsAbstract" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems to ReconciliationOfChangesInRightofuseAssetsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DepreciationRightofuseAssets" xlink:label="DepreciationRightofuseAssets" xlink:title="DepreciationRightofuseAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="DepreciationRightofuseAssets" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems to DepreciationRightofuseAssets" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" xlink:label="DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" xlink:title="DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems to DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfAssetsAxis" xlink:label="ClassesOfAssetsAxis" xlink:title="ClassesOfAssetsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" xlink:to="ClassesOfAssetsAxis" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable to ClassesOfAssetsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfAssetsDomain" xlink:label="ClassesOfAssetsDomain" xlink:title="ClassesOfAssetsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ClassesOfAssetsAxis" xlink:to="ClassesOfAssetsDomain" xlink:title="definition: ClassesOfAssetsAxis to ClassesOfAssetsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfAssetsDomain" xlink:label="ClassesOfAssetsDomain_2" xlink:title="ClassesOfAssetsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassesOfAssetsAxis" xlink:to="ClassesOfAssetsDomain_2" xlink:title="definition: ClassesOfAssetsAxis to ClassesOfAssetsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PropertiesMember" xlink:label="PropertiesMember" xlink:title="PropertiesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfAssetsDomain" xlink:to="PropertiesMember" xlink:title="definition: ClassesOfAssetsDomain to PropertiesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MotorVehiclesMember" xlink:label="MotorVehiclesMember" xlink:title="MotorVehiclesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfAssetsDomain" xlink:to="MotorVehiclesMember" xlink:title="definition: ClassesOfAssetsDomain to MotorVehiclesMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/IntangibleAssetsNetBookAmountDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfIntangibleAssetsLineItems" xlink:label="DisclosureOfIntangibleAssetsLineItems" xlink:title="DisclosureOfIntangibleAssetsLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ReconciliationOfChangesInIntangibleAssetsOtherThanGoodwillAbstract" xlink:label="ReconciliationOfChangesInIntangibleAssetsOtherThanGoodwillAbstract" xlink:title="ReconciliationOfChangesInIntangibleAssetsOtherThanGoodwillAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfIntangibleAssetsLineItems" xlink:to="ReconciliationOfChangesInIntangibleAssetsOtherThanGoodwillAbstract" xlink:title="definition: DisclosureOfIntangibleAssetsLineItems to ReconciliationOfChangesInIntangibleAssetsOtherThanGoodwillAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IntangibleAssetsOtherThanGoodwill" xlink:label="IntangibleAssetsOtherThanGoodwill" xlink:title="IntangibleAssetsOtherThanGoodwill" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfIntangibleAssetsLineItems" xlink:to="IntangibleAssetsOtherThanGoodwill" xlink:title="definition: DisclosureOfIntangibleAssetsLineItems to IntangibleAssetsOtherThanGoodwill" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AcquisitionsThroughBusinessCombinationsIntangibleAssetsOtherThanGoodwill" xlink:label="AcquisitionsThroughBusinessCombinationsIntangibleAssetsOtherThanGoodwill" xlink:title="AcquisitionsThroughBusinessCombinationsIntangibleAssetsOtherThanGoodwill" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfIntangibleAssetsLineItems" xlink:to="AcquisitionsThroughBusinessCombinationsIntangibleAssetsOtherThanGoodwill" xlink:title="definition: DisclosureOfIntangibleAssetsLineItems to AcquisitionsThroughBusinessCombinationsIntangibleAssetsOtherThanGoodwill" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AdditionsOtherThanThroughBusinessCombinationsIntangibleAssetsOtherThanGoodwill" xlink:label="AdditionsOtherThanThroughBusinessCombinationsIntangibleAssetsOtherThanGoodwill" xlink:title="AdditionsOtherThanThroughBusinessCombinationsIntangibleAssetsOtherThanGoodwill" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfIntangibleAssetsLineItems" xlink:to="AdditionsOtherThanThroughBusinessCombinationsIntangibleAssetsOtherThanGoodwill" xlink:title="definition: DisclosureOfIntangibleAssetsLineItems to AdditionsOtherThanThroughBusinessCombinationsIntangibleAssetsOtherThanGoodwill" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ReclassificationsIncreaseDecreaseIntangibleAssetsOtherThanGoodwill" xlink:label="ReclassificationsIncreaseDecreaseIntangibleAssetsOtherThanGoodwill" xlink:title="ReclassificationsIncreaseDecreaseIntangibleAssetsOtherThanGoodwill" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfIntangibleAssetsLineItems" xlink:to="ReclassificationsIncreaseDecreaseIntangibleAssetsOtherThanGoodwill" xlink:title="definition: DisclosureOfIntangibleAssetsLineItems to ReclassificationsIncreaseDecreaseIntangibleAssetsOtherThanGoodwill" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AmortisationIntangibleAssetsOtherThanGoodwill" xlink:label="AmortisationIntangibleAssetsOtherThanGoodwill" xlink:title="AmortisationIntangibleAssetsOtherThanGoodwill" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfIntangibleAssetsLineItems" xlink:to="AmortisationIntangibleAssetsOtherThanGoodwill" xlink:title="definition: DisclosureOfIntangibleAssetsLineItems to AmortisationIntangibleAssetsOtherThanGoodwill" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ReversalOfImpairmentLossRecognisedInProfitOrLossIntangibleAssetsOtherThanGoodwill" xlink:label="ReversalOfImpairmentLossRecognisedInProfitOrLossIntangibleAssetsOtherThanGoodwill" xlink:title="ReversalOfImpairmentLossRecognisedInProfitOrLossIntangibleAssetsOtherThanGoodwill" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfIntangibleAssetsLineItems" xlink:to="ReversalOfImpairmentLossRecognisedInProfitOrLossIntangibleAssetsOtherThanGoodwill" xlink:title="definition: DisclosureOfIntangibleAssetsLineItems to ReversalOfImpairmentLossRecognisedInProfitOrLossIntangibleAssetsOtherThanGoodwill" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ImpairmentLossRecognisedInProfitOrLossIntangibleAssetsOtherThanGoodwill" xlink:label="ImpairmentLossRecognisedInProfitOrLossIntangibleAssetsOtherThanGoodwill" xlink:title="ImpairmentLossRecognisedInProfitOrLossIntangibleAssetsOtherThanGoodwill" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfIntangibleAssetsLineItems" xlink:to="ImpairmentLossRecognisedInProfitOrLossIntangibleAssetsOtherThanGoodwill" xlink:title="definition: DisclosureOfIntangibleAssetsLineItems to ImpairmentLossRecognisedInProfitOrLossIntangibleAssetsOtherThanGoodwill" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseThroughChangesInProvisionsIntangibleAssetsOtherThanGoodwill" xlink:label="IncreaseDecreaseThroughChangesInProvisionsIntangibleAssetsOtherThanGoodwill" xlink:title="IncreaseDecreaseThroughChangesInProvisionsIntangibleAssetsOtherThanGoodwill" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfIntangibleAssetsLineItems" xlink:to="IncreaseDecreaseThroughChangesInProvisionsIntangibleAssetsOtherThanGoodwill" xlink:title="definition: DisclosureOfIntangibleAssetsLineItems to IncreaseDecreaseThroughChangesInProvisionsIntangibleAssetsOtherThanGoodwill" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughNetExchangeDifferencesIntangibleAssetsOtherThanGoodwill" xlink:label="IncreaseDecreaseThroughNetExchangeDifferencesIntangibleAssetsOtherThanGoodwill" xlink:title="IncreaseDecreaseThroughNetExchangeDifferencesIntangibleAssetsOtherThanGoodwill" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfIntangibleAssetsLineItems" xlink:to="IncreaseDecreaseThroughNetExchangeDifferencesIntangibleAssetsOtherThanGoodwill" xlink:title="definition: DisclosureOfIntangibleAssetsLineItems to IncreaseDecreaseThroughNetExchangeDifferencesIntangibleAssetsOtherThanGoodwill" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IntangibleAssetsAtCost" xlink:label="IntangibleAssetsAtCost" xlink:title="IntangibleAssetsAtCost" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfIntangibleAssetsLineItems" xlink:to="IntangibleAssetsAtCost" xlink:title="definition: DisclosureOfIntangibleAssetsLineItems to IntangibleAssetsAtCost" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AccumulatedAmortizationIntangibleAssets" xlink:label="AccumulatedAmortizationIntangibleAssets" xlink:title="AccumulatedAmortizationIntangibleAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfIntangibleAssetsLineItems" xlink:to="AccumulatedAmortizationIntangibleAssets" xlink:title="definition: DisclosureOfIntangibleAssetsLineItems to AccumulatedAmortizationIntangibleAssets" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfIntangibleAssetsTable" xlink:label="DisclosureOfIntangibleAssetsTable" xlink:title="DisclosureOfIntangibleAssetsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfIntangibleAssetsLineItems" xlink:to="DisclosureOfIntangibleAssetsTable" xlink:title="definition: DisclosureOfIntangibleAssetsLineItems to DisclosureOfIntangibleAssetsTable" order="13.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillAxis" xlink:label="ClassesOfIntangibleAssetsOtherThanGoodwillAxis" xlink:title="ClassesOfIntangibleAssetsOtherThanGoodwillAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfIntangibleAssetsTable" xlink:to="ClassesOfIntangibleAssetsOtherThanGoodwillAxis" xlink:title="definition: DisclosureOfIntangibleAssetsTable to ClassesOfIntangibleAssetsOtherThanGoodwillAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:label="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:title="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ClassesOfIntangibleAssetsOtherThanGoodwillAxis" xlink:to="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:title="definition: ClassesOfIntangibleAssetsOtherThanGoodwillAxis to ClassesOfIntangibleAssetsOtherThanGoodwillDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:label="ClassesOfIntangibleAssetsOtherThanGoodwillDomain_2" xlink:title="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassesOfIntangibleAssetsOtherThanGoodwillAxis" xlink:to="ClassesOfIntangibleAssetsOtherThanGoodwillDomain_2" xlink:title="definition: ClassesOfIntangibleAssetsOtherThanGoodwillAxis to ClassesOfIntangibleAssetsOtherThanGoodwillDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GoodwillMember" xlink:label="GoodwillMember" xlink:title="GoodwillMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:to="GoodwillMember" xlink:title="definition: ClassesOfIntangibleAssetsOtherThanGoodwillDomain to GoodwillMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BrandNamesMember" xlink:label="BrandNamesMember" xlink:title="BrandNamesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:to="BrandNamesMember" xlink:title="definition: ClassesOfIntangibleAssetsOtherThanGoodwillDomain to BrandNamesMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_CustomerRelationshipsAndBrandsMember" xlink:label="CustomerRelationshipsAndBrandsMember" xlink:title="CustomerRelationshipsAndBrandsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:to="CustomerRelationshipsAndBrandsMember" xlink:title="definition: ClassesOfIntangibleAssetsOtherThanGoodwillDomain to CustomerRelationshipsAndBrandsMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComputerSoftwareMember" xlink:label="ComputerSoftwareMember" xlink:title="ComputerSoftwareMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:to="ComputerSoftwareMember" xlink:title="definition: ClassesOfIntangibleAssetsOtherThanGoodwillDomain to ComputerSoftwareMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CopyrightsPatentsAndOtherIndustrialPropertyRightsServiceAndOperatingRightsMember" xlink:label="CopyrightsPatentsAndOtherIndustrialPropertyRightsServiceAndOperatingRightsMember" xlink:title="CopyrightsPatentsAndOtherIndustrialPropertyRightsServiceAndOperatingRightsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:to="CopyrightsPatentsAndOtherIndustrialPropertyRightsServiceAndOperatingRightsMember" xlink:title="definition: ClassesOfIntangibleAssetsOtherThanGoodwillDomain to CopyrightsPatentsAndOtherIndustrialPropertyRightsServiceAndOperatingRightsMember" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LicencesMember" xlink:label="LicencesMember" xlink:title="LicencesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:to="LicencesMember" xlink:title="definition: ClassesOfIntangibleAssetsOtherThanGoodwillDomain to LicencesMember" order="6.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/IntangibleAssetsCashGeneratingUnitsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesLineItems" xlink:label="DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesLineItems" xlink:title="DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesAbstract" xlink:label="DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesAbstract" xlink:title="DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesLineItems" xlink:to="DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesAbstract" xlink:title="definition: DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesLineItems to DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DescriptionOfUsefulLifeIntangibleAssetsOtherThanGoodwill" xlink:label="DescriptionOfUsefulLifeIntangibleAssetsOtherThanGoodwill" xlink:title="DescriptionOfUsefulLifeIntangibleAssetsOtherThanGoodwill" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesLineItems" xlink:to="DescriptionOfUsefulLifeIntangibleAssetsOtherThanGoodwill" xlink:title="definition: DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesLineItems to DescriptionOfUsefulLifeIntangibleAssetsOtherThanGoodwill" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DescriptionOfCashgeneratingUnit" xlink:label="DescriptionOfCashgeneratingUnit" xlink:title="DescriptionOfCashgeneratingUnit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesLineItems" xlink:to="DescriptionOfCashgeneratingUnit" xlink:title="definition: DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesLineItems to DescriptionOfCashgeneratingUnit" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IntangibleAssetsOtherThanGoodwill" xlink:label="IntangibleAssetsOtherThanGoodwill" xlink:title="IntangibleAssetsOtherThanGoodwill" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesLineItems" xlink:to="IntangibleAssetsOtherThanGoodwill" xlink:title="definition: DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesLineItems to IntangibleAssetsOtherThanGoodwill" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesTable" xlink:label="DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesTable" xlink:title="DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesLineItems" xlink:to="DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesTable" xlink:title="definition: DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesLineItems to DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesTable" order="5.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProductsAndServicesAxis" xlink:label="ProductsAndServicesAxis" xlink:title="ProductsAndServicesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesTable" xlink:to="ProductsAndServicesAxis" xlink:title="definition: DisclosureOfInformationForIndividualAssetOrCashgeneratingUnitWithSignificantAmountOfGoodwillOrIntangibleAssetsWithIndefiniteUsefulLivesTable to ProductsAndServicesAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProductsAndServicesDomain" xlink:label="ProductsAndServicesDomain" xlink:title="ProductsAndServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ProductsAndServicesAxis" xlink:to="ProductsAndServicesDomain" xlink:title="definition: ProductsAndServicesAxis to ProductsAndServicesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProductsAndServicesDomain" xlink:label="ProductsAndServicesDomain_2" xlink:title="ProductsAndServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ProductsAndServicesAxis" xlink:to="ProductsAndServicesDomain_2" xlink:title="definition: ProductsAndServicesAxis to ProductsAndServicesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TLX591CDxIlluccixMember" xlink:label="TLX591CDxIlluccixMember" xlink:title="TLX591CDxIlluccixMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="TLX591CDxIlluccixMember" xlink:title="definition: ProductsAndServicesDomain to TLX591CDxIlluccixMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TLX66-CDxMember" xlink:label="TLX66-CDxMember" xlink:title="TLX66-CDxMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="TLX66-CDxMember" xlink:title="definition: ProductsAndServicesDomain to TLX66-CDxMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CopyrightsPatentsAndOtherIndustrialPropertyRightsServiceAndOperatingRightsMember" xlink:label="CopyrightsPatentsAndOtherIndustrialPropertyRightsServiceAndOperatingRightsMember" xlink:title="CopyrightsPatentsAndOtherIndustrialPropertyRightsServiceAndOperatingRightsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="CopyrightsPatentsAndOtherIndustrialPropertyRightsServiceAndOperatingRightsMember" xlink:title="definition: ProductsAndServicesDomain to CopyrightsPatentsAndOtherIndustrialPropertyRightsServiceAndOperatingRightsMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_SENSEIMember" xlink:label="SENSEIMember" xlink:title="SENSEIMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="SENSEIMember" xlink:title="definition: ProductsAndServicesDomain to SENSEIMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DedicaidQDOSEMember" xlink:label="DedicaidQDOSEMember" xlink:title="DedicaidQDOSEMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="DedicaidQDOSEMember" xlink:title="definition: ProductsAndServicesDomain to DedicaidQDOSEMember" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TLX101Member" xlink:label="TLX101Member" xlink:title="TLX101Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="TLX101Member" xlink:title="definition: ProductsAndServicesDomain to TLX101Member" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_QSAM153SmDOTMPMember" xlink:label="QSAM153SmDOTMPMember" xlink:title="QSAM153SmDOTMPMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="QSAM153SmDOTMPMember" xlink:title="definition: ProductsAndServicesDomain to QSAM153SmDOTMPMember" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TLX591Member" xlink:label="TLX591Member" xlink:title="TLX591Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="TLX591Member" xlink:title="definition: ProductsAndServicesDomain to TLX591Member" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TLX66Member" xlink:label="TLX66Member" xlink:title="TLX66Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="TLX66Member" xlink:title="definition: ProductsAndServicesDomain to TLX66Member" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TLX300Member" xlink:label="TLX300Member" xlink:title="TLX300Member" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="TLX300Member" xlink:title="definition: ProductsAndServicesDomain to TLX300Member" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ARTMSMember" xlink:label="ARTMSMember" xlink:title="ARTMSMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="ARTMSMember" xlink:title="definition: ProductsAndServicesDomain to ARTMSMember" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IsoTherapeuticsMember" xlink:label="IsoTherapeuticsMember" xlink:title="IsoTherapeuticsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="IsoTherapeuticsMember" xlink:title="definition: ProductsAndServicesDomain to IsoTherapeuticsMember" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_BrusselsSouthAndOptimalTracersMember" xlink:label="BrusselsSouthAndOptimalTracersMember" xlink:title="BrusselsSouthAndOptimalTracersMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="BrusselsSouthAndOptimalTracersMember" xlink:title="definition: ProductsAndServicesDomain to BrusselsSouthAndOptimalTracersMember" order="13.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/IntangibleAssetsImpairmentDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/AcquisitionsIsotherapeuticsGroupLlcDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfBusinessCombinationsLineItems" xlink:label="DisclosureOfBusinessCombinationsLineItems" xlink:title="DisclosureOfBusinessCombinationsLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AcquisitionAbstract" xlink:label="AcquisitionAbstract" xlink:title="AcquisitionAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AcquisitionAbstract" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AcquisitionAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" xlink:label="AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" xlink:title="AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AmountsRecognisedAsOfAcquisitionDateForEachMajorClassOfAssetsAcquiredAndLiabilitiesAssumedAbstract" xlink:label="AmountsRecognisedAsOfAcquisitionDateForEachMajorClassOfAssetsAcquiredAndLiabilitiesAssumedAbstract" xlink:title="AmountsRecognisedAsOfAcquisitionDateForEachMajorClassOfAssetsAcquiredAndLiabilitiesAssumedAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AmountsRecognisedAsOfAcquisitionDateForEachMajorClassOfAssetsAcquiredAndLiabilitiesAssumedAbstract" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AmountsRecognisedAsOfAcquisitionDateForEachMajorClassOfAssetsAcquiredAndLiabilitiesAssumedAbstract" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_FairValueAdjustmentsAbstract" xlink:label="FairValueAdjustmentsAbstract" xlink:title="FairValueAdjustmentsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="FairValueAdjustmentsAbstract" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to FairValueAdjustmentsAbstract" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UsefulLifeMeasuredAsPeriodOfTimeIntangibleAssetsOtherThanGoodwill" xlink:label="UsefulLifeMeasuredAsPeriodOfTimeIntangibleAssetsOtherThanGoodwill" xlink:title="UsefulLifeMeasuredAsPeriodOfTimeIntangibleAssetsOtherThanGoodwill" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="UsefulLifeMeasuredAsPeriodOfTimeIntangibleAssetsOtherThanGoodwill" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to UsefulLifeMeasuredAsPeriodOfTimeIntangibleAssetsOtherThanGoodwill" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AcquisitionrelatedCostsRecognisedAsExpenseForTransactionRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombination" xlink:label="AcquisitionrelatedCostsRecognisedAsExpenseForTransactionRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombination" xlink:title="AcquisitionrelatedCostsRecognisedAsExpenseForTransactionRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombination" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AcquisitionrelatedCostsRecognisedAsExpenseForTransactionRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombination" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AcquisitionrelatedCostsRecognisedAsExpenseForTransactionRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombination" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RevenueOfAcquiree" xlink:label="RevenueOfAcquiree" xlink:title="RevenueOfAcquiree" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="RevenueOfAcquiree" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to RevenueOfAcquiree" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProfitLossOfAcquiree" xlink:label="ProfitLossOfAcquiree" xlink:title="ProfitLossOfAcquiree" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="ProfitLossOfAcquiree" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to ProfitLossOfAcquiree" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseOfRevenueOfCombinedEntity" xlink:label="IncreaseDecreaseOfRevenueOfCombinedEntity" xlink:title="IncreaseDecreaseOfRevenueOfCombinedEntity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="IncreaseDecreaseOfRevenueOfCombinedEntity" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to IncreaseDecreaseOfRevenueOfCombinedEntity" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseOfProfitLossBeforeTaxOfCombinedEntity" xlink:label="IncreaseDecreaseOfProfitLossBeforeTaxOfCombinedEntity" xlink:title="IncreaseDecreaseOfProfitLossBeforeTaxOfCombinedEntity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="IncreaseDecreaseOfProfitLossBeforeTaxOfCombinedEntity" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to IncreaseDecreaseOfProfitLossBeforeTaxOfCombinedEntity" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_FairValueAdjustmentCustomerRelationships" xlink:label="FairValueAdjustmentCustomerRelationships" xlink:title="FairValueAdjustmentCustomerRelationships" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="FairValueAdjustmentCustomerRelationships" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to FairValueAdjustmentCustomerRelationships" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_FairValueAdjustmentBrandName" xlink:label="FairValueAdjustmentBrandName" xlink:title="FairValueAdjustmentBrandName" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="FairValueAdjustmentBrandName" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to FairValueAdjustmentBrandName" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_FairValueAdjustmentDeferredTaxLiability" xlink:label="FairValueAdjustmentDeferredTaxLiability" xlink:title="FairValueAdjustmentDeferredTaxLiability" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="FairValueAdjustmentDeferredTaxLiability" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to FairValueAdjustmentDeferredTaxLiability" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_FairValueAdjustmentsRecognizedAsOfAcquisitionDate" xlink:label="FairValueAdjustmentsRecognizedAsOfAcquisitionDate" xlink:title="FairValueAdjustmentsRecognizedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="FairValueAdjustmentsRecognizedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to FairValueAdjustmentsRecognizedAsOfAcquisitionDate" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GoodwillRecognisedAsOfAcquisitionDate" xlink:label="GoodwillRecognisedAsOfAcquisitionDate" xlink:title="GoodwillRecognisedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="GoodwillRecognisedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to GoodwillRecognisedAsOfAcquisitionDate" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AcquisitiondateFairValueOfTotalConsiderationTransferred" xlink:label="AcquisitiondateFairValueOfTotalConsiderationTransferred" xlink:title="AcquisitiondateFairValueOfTotalConsiderationTransferred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AcquisitiondateFairValueOfTotalConsiderationTransferred" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AcquisitiondateFairValueOfTotalConsiderationTransferred" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashAndCashEquivalentsRecognisedAsOfAcquisitionDate" xlink:label="CashAndCashEquivalentsRecognisedAsOfAcquisitionDate" xlink:title="CashAndCashEquivalentsRecognisedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="CashAndCashEquivalentsRecognisedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to CashAndCashEquivalentsRecognisedAsOfAcquisitionDate" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TradeAndOtherReceivablesRecognizedAsOfAcquisitionDate" xlink:label="TradeAndOtherReceivablesRecognizedAsOfAcquisitionDate" xlink:title="TradeAndOtherReceivablesRecognizedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="TradeAndOtherReceivablesRecognizedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to TradeAndOtherReceivablesRecognizedAsOfAcquisitionDate" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PropertyPlantAndEquipmentRecognisedAsOfAcquisitionDate" xlink:label="PropertyPlantAndEquipmentRecognisedAsOfAcquisitionDate" xlink:title="PropertyPlantAndEquipmentRecognisedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="PropertyPlantAndEquipmentRecognisedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to PropertyPlantAndEquipmentRecognisedAsOfAcquisitionDate" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_RightOfUseAssetsRecognizedAsOfAcquisitionDate" xlink:label="RightOfUseAssetsRecognizedAsOfAcquisitionDate" xlink:title="RightOfUseAssetsRecognizedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="RightOfUseAssetsRecognizedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to RightOfUseAssetsRecognizedAsOfAcquisitionDate" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TradeAndOtherPayablesRecognisedAsOfAcquisitionDate" xlink:label="TradeAndOtherPayablesRecognisedAsOfAcquisitionDate" xlink:title="TradeAndOtherPayablesRecognisedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="TradeAndOtherPayablesRecognisedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to TradeAndOtherPayablesRecognisedAsOfAcquisitionDate" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_LeaseLiabilitiesAdjustmentsRecognizedAsOfAcquisitionDate" xlink:label="LeaseLiabilitiesAdjustmentsRecognizedAsOfAcquisitionDate" xlink:title="LeaseLiabilitiesAdjustmentsRecognizedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="LeaseLiabilitiesAdjustmentsRecognizedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to LeaseLiabilitiesAdjustmentsRecognizedAsOfAcquisitionDate" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IdentifiableAssetsAcquiredLiabilitiesAssumed" xlink:label="IdentifiableAssetsAcquiredLiabilitiesAssumed" xlink:title="IdentifiableAssetsAcquiredLiabilitiesAssumed" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="IdentifiableAssetsAcquiredLiabilitiesAssumed" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to IdentifiableAssetsAcquiredLiabilitiesAssumed" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashTransferred" xlink:label="CashTransferred" xlink:title="CashTransferred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="CashTransferred" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to CashTransferred" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_EquityInterestsOfAcquirer" xlink:label="EquityInterestsOfAcquirer" xlink:title="EquityInterestsOfAcquirer" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="EquityInterestsOfAcquirer" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to EquityInterestsOfAcquirer" order="25.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesIncurred" xlink:label="LiabilitiesIncurred" xlink:title="LiabilitiesIncurred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="LiabilitiesIncurred" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to LiabilitiesIncurred" order="26.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfSharesOutstanding" xlink:label="NumberOfSharesOutstanding" xlink:title="NumberOfSharesOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="NumberOfSharesOutstanding" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to NumberOfSharesOutstanding" order="27.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ParValuePerShare" xlink:label="ParValuePerShare" xlink:title="ParValuePerShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="ParValuePerShare" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to ParValuePerShare" order="28.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PercentageOfNetRevenuePayableInCashAsPerformanceBasedPayments" xlink:label="PercentageOfNetRevenuePayableInCashAsPerformanceBasedPayments" xlink:title="PercentageOfNetRevenuePayableInCashAsPerformanceBasedPayments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="PercentageOfNetRevenuePayableInCashAsPerformanceBasedPayments" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to PercentageOfNetRevenuePayableInCashAsPerformanceBasedPayments" order="29.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_RevenueSharingPeriod" xlink:label="RevenueSharingPeriod" xlink:title="RevenueSharingPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="RevenueSharingPeriod" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to RevenueSharingPeriod" order="30.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfBusinessCombinationsTable" xlink:label="DisclosureOfBusinessCombinationsTable" xlink:title="DisclosureOfBusinessCombinationsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="DisclosureOfBusinessCombinationsTable" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to DisclosureOfBusinessCombinationsTable" order="31.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsAxis" xlink:label="BusinessCombinationsAxis" xlink:title="BusinessCombinationsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfBusinessCombinationsTable" xlink:to="BusinessCombinationsAxis" xlink:title="definition: DisclosureOfBusinessCombinationsTable to BusinessCombinationsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain_2" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain_2" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsMember" xlink:label="BusinessCombinationsMember" xlink:title="BusinessCombinationsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="BusinessCombinationsMember" xlink:title="definition: BusinessCombinationsDomain to BusinessCombinationsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IsoTherapeuticsGroupLLCMember" xlink:label="IsoTherapeuticsGroupLLCMember" xlink:title="IsoTherapeuticsGroupLLCMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsMember" xlink:to="IsoTherapeuticsGroupLLCMember" xlink:title="definition: BusinessCombinationsMember to IsoTherapeuticsGroupLLCMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillAxis" xlink:label="ClassesOfIntangibleAssetsOtherThanGoodwillAxis" xlink:title="ClassesOfIntangibleAssetsOtherThanGoodwillAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfBusinessCombinationsTable" xlink:to="ClassesOfIntangibleAssetsOtherThanGoodwillAxis" xlink:title="definition: DisclosureOfBusinessCombinationsTable to ClassesOfIntangibleAssetsOtherThanGoodwillAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:label="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:title="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ClassesOfIntangibleAssetsOtherThanGoodwillAxis" xlink:to="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:title="definition: ClassesOfIntangibleAssetsOtherThanGoodwillAxis to ClassesOfIntangibleAssetsOtherThanGoodwillDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:label="ClassesOfIntangibleAssetsOtherThanGoodwillDomain_2" xlink:title="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassesOfIntangibleAssetsOtherThanGoodwillAxis" xlink:to="ClassesOfIntangibleAssetsOtherThanGoodwillDomain_2" xlink:title="definition: ClassesOfIntangibleAssetsOtherThanGoodwillAxis to ClassesOfIntangibleAssetsOtherThanGoodwillDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CustomerrelatedIntangibleAssetsMember" xlink:label="CustomerrelatedIntangibleAssetsMember" xlink:title="CustomerrelatedIntangibleAssetsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:to="CustomerrelatedIntangibleAssetsMember" xlink:title="definition: ClassesOfIntangibleAssetsOtherThanGoodwillDomain to CustomerrelatedIntangibleAssetsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BrandNamesMember" xlink:label="BrandNamesMember" xlink:title="BrandNamesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfIntangibleAssetsOtherThanGoodwillDomain" xlink:to="BrandNamesMember" xlink:title="definition: ClassesOfIntangibleAssetsOtherThanGoodwillDomain to BrandNamesMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/AcquisitionsArtmsIncDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfBusinessCombinationsLineItems" xlink:label="DisclosureOfBusinessCombinationsLineItems" xlink:title="DisclosureOfBusinessCombinationsLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AcquisitionAbstract" xlink:label="AcquisitionAbstract" xlink:title="AcquisitionAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AcquisitionAbstract" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AcquisitionAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" xlink:label="AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" xlink:title="AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AmountsRecognisedAsOfAcquisitionDateForEachMajorClassOfAssetsAcquiredAndLiabilitiesAssumedAbstract" xlink:label="AmountsRecognisedAsOfAcquisitionDateForEachMajorClassOfAssetsAcquiredAndLiabilitiesAssumedAbstract" xlink:title="AmountsRecognisedAsOfAcquisitionDateForEachMajorClassOfAssetsAcquiredAndLiabilitiesAssumedAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AmountsRecognisedAsOfAcquisitionDateForEachMajorClassOfAssetsAcquiredAndLiabilitiesAssumedAbstract" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AmountsRecognisedAsOfAcquisitionDateForEachMajorClassOfAssetsAcquiredAndLiabilitiesAssumedAbstract" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_FairValueAdjustmentsAbstract" xlink:label="FairValueAdjustmentsAbstract" xlink:title="FairValueAdjustmentsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="FairValueAdjustmentsAbstract" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to FairValueAdjustmentsAbstract" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GoodwillRecognisedAsOfAcquisitionDate" xlink:label="GoodwillRecognisedAsOfAcquisitionDate" xlink:title="GoodwillRecognisedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="GoodwillRecognisedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to GoodwillRecognisedAsOfAcquisitionDate" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AcquisitiondateFairValueOfTotalConsiderationTransferred" xlink:label="AcquisitiondateFairValueOfTotalConsiderationTransferred" xlink:title="AcquisitiondateFairValueOfTotalConsiderationTransferred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AcquisitiondateFairValueOfTotalConsiderationTransferred" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AcquisitiondateFairValueOfTotalConsiderationTransferred" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AcquisitionrelatedCostsRecognisedAsExpenseForTransactionRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombination" xlink:label="AcquisitionrelatedCostsRecognisedAsExpenseForTransactionRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombination" xlink:title="AcquisitionrelatedCostsRecognisedAsExpenseForTransactionRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombination" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AcquisitionrelatedCostsRecognisedAsExpenseForTransactionRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombination" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AcquisitionrelatedCostsRecognisedAsExpenseForTransactionRecognisedSeparatelyFromAcquisitionOfAssetsAndAssumptionOfLiabilitiesInBusinessCombination" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RevenueOfAcquiree" xlink:label="RevenueOfAcquiree" xlink:title="RevenueOfAcquiree" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="RevenueOfAcquiree" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to RevenueOfAcquiree" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProfitLossOfAcquiree" xlink:label="ProfitLossOfAcquiree" xlink:title="ProfitLossOfAcquiree" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="ProfitLossOfAcquiree" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to ProfitLossOfAcquiree" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseOfRevenueOfCombinedEntity" xlink:label="IncreaseDecreaseOfRevenueOfCombinedEntity" xlink:title="IncreaseDecreaseOfRevenueOfCombinedEntity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="IncreaseDecreaseOfRevenueOfCombinedEntity" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to IncreaseDecreaseOfRevenueOfCombinedEntity" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseOfProfitLossBeforeTaxOfCombinedEntity" xlink:label="IncreaseDecreaseOfProfitLossBeforeTaxOfCombinedEntity" xlink:title="IncreaseDecreaseOfProfitLossBeforeTaxOfCombinedEntity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="IncreaseDecreaseOfProfitLossBeforeTaxOfCombinedEntity" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to IncreaseDecreaseOfProfitLossBeforeTaxOfCombinedEntity" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_FairValueAdjustmentIntellectualProperty" xlink:label="FairValueAdjustmentIntellectualProperty" xlink:title="FairValueAdjustmentIntellectualProperty" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="FairValueAdjustmentIntellectualProperty" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to FairValueAdjustmentIntellectualProperty" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_FairValueAdjustmentDeferredTaxLiability" xlink:label="FairValueAdjustmentDeferredTaxLiability" xlink:title="FairValueAdjustmentDeferredTaxLiability" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="FairValueAdjustmentDeferredTaxLiability" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to FairValueAdjustmentDeferredTaxLiability" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_FairValueAdjustmentPropertyPlantAndEquipment" xlink:label="FairValueAdjustmentPropertyPlantAndEquipment" xlink:title="FairValueAdjustmentPropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="FairValueAdjustmentPropertyPlantAndEquipment" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to FairValueAdjustmentPropertyPlantAndEquipment" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_FairValueAdjustmentPropertyInventories" xlink:label="FairValueAdjustmentPropertyInventories" xlink:title="FairValueAdjustmentPropertyInventories" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="FairValueAdjustmentPropertyInventories" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to FairValueAdjustmentPropertyInventories" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_FairValueAdjustmentsRecognizedAsOfAcquisitionDate" xlink:label="FairValueAdjustmentsRecognizedAsOfAcquisitionDate" xlink:title="FairValueAdjustmentsRecognizedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="FairValueAdjustmentsRecognizedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to FairValueAdjustmentsRecognizedAsOfAcquisitionDate" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashAndCashEquivalentsRecognisedAsOfAcquisitionDate" xlink:label="CashAndCashEquivalentsRecognisedAsOfAcquisitionDate" xlink:title="CashAndCashEquivalentsRecognisedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="CashAndCashEquivalentsRecognisedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to CashAndCashEquivalentsRecognisedAsOfAcquisitionDate" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TradeAndOtherReceivablesRecognizedAsOfAcquisitionDate" xlink:label="TradeAndOtherReceivablesRecognizedAsOfAcquisitionDate" xlink:title="TradeAndOtherReceivablesRecognizedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="TradeAndOtherReceivablesRecognizedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to TradeAndOtherReceivablesRecognizedAsOfAcquisitionDate" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrentAssetsRecognisedAsOfAcquisitionDate" xlink:label="CurrentAssetsRecognisedAsOfAcquisitionDate" xlink:title="CurrentAssetsRecognisedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="CurrentAssetsRecognisedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to CurrentAssetsRecognisedAsOfAcquisitionDate" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_InventoryRecognisedAsOfAcquisitionDate" xlink:label="InventoryRecognisedAsOfAcquisitionDate" xlink:title="InventoryRecognisedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="InventoryRecognisedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to InventoryRecognisedAsOfAcquisitionDate" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncurrentAssetsRecognisedAsOfAcquisitionDate" xlink:label="NoncurrentAssetsRecognisedAsOfAcquisitionDate" xlink:title="NoncurrentAssetsRecognisedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="NoncurrentAssetsRecognisedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to NoncurrentAssetsRecognisedAsOfAcquisitionDate" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PropertyPlantAndEquipmentRecognisedAsOfAcquisitionDate" xlink:label="PropertyPlantAndEquipmentRecognisedAsOfAcquisitionDate" xlink:title="PropertyPlantAndEquipmentRecognisedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="PropertyPlantAndEquipmentRecognisedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to PropertyPlantAndEquipmentRecognisedAsOfAcquisitionDate" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_RightOfUseAssetsRecognizedAsOfAcquisitionDate" xlink:label="RightOfUseAssetsRecognizedAsOfAcquisitionDate" xlink:title="RightOfUseAssetsRecognizedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="RightOfUseAssetsRecognizedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to RightOfUseAssetsRecognizedAsOfAcquisitionDate" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TradeAndOtherPayablesRecognisedAsOfAcquisitionDate" xlink:label="TradeAndOtherPayablesRecognisedAsOfAcquisitionDate" xlink:title="TradeAndOtherPayablesRecognisedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="TradeAndOtherPayablesRecognisedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to TradeAndOtherPayablesRecognisedAsOfAcquisitionDate" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_LeaseLiabilitiesAdjustmentsRecognizedAsOfAcquisitionDate" xlink:label="LeaseLiabilitiesAdjustmentsRecognizedAsOfAcquisitionDate" xlink:title="LeaseLiabilitiesAdjustmentsRecognizedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="LeaseLiabilitiesAdjustmentsRecognizedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to LeaseLiabilitiesAdjustmentsRecognizedAsOfAcquisitionDate" order="25.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IdentifiableAssetsAcquiredLiabilitiesAssumed" xlink:label="IdentifiableAssetsAcquiredLiabilitiesAssumed" xlink:title="IdentifiableAssetsAcquiredLiabilitiesAssumed" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="IdentifiableAssetsAcquiredLiabilitiesAssumed" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to IdentifiableAssetsAcquiredLiabilitiesAssumed" order="26.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashTransferred" xlink:label="CashTransferred" xlink:title="CashTransferred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="CashTransferred" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to CashTransferred" order="27.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_EquityInterestsOfAcquirer" xlink:label="EquityInterestsOfAcquirer" xlink:title="EquityInterestsOfAcquirer" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="EquityInterestsOfAcquirer" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to EquityInterestsOfAcquirer" order="28.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesIncurred" xlink:label="LiabilitiesIncurred" xlink:title="LiabilitiesIncurred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="LiabilitiesIncurred" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to LiabilitiesIncurred" order="29.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfSharesOutstanding" xlink:label="NumberOfSharesOutstanding" xlink:title="NumberOfSharesOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="NumberOfSharesOutstanding" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to NumberOfSharesOutstanding" order="30.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ParValuePerShare" xlink:label="ParValuePerShare" xlink:title="ParValuePerShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="ParValuePerShare" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to ParValuePerShare" order="31.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TerminationPeriodOfEarnOuts" xlink:label="TerminationPeriodOfEarnOuts" xlink:title="TerminationPeriodOfEarnOuts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="TerminationPeriodOfEarnOuts" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to TerminationPeriodOfEarnOuts" order="32.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfBusinessCombinationsTable" xlink:label="DisclosureOfBusinessCombinationsTable" xlink:title="DisclosureOfBusinessCombinationsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="DisclosureOfBusinessCombinationsTable" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to DisclosureOfBusinessCombinationsTable" order="33.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsAxis" xlink:label="BusinessCombinationsAxis" xlink:title="BusinessCombinationsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfBusinessCombinationsTable" xlink:to="BusinessCombinationsAxis" xlink:title="definition: DisclosureOfBusinessCombinationsTable to BusinessCombinationsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain_2" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain_2" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsMember" xlink:label="BusinessCombinationsMember" xlink:title="BusinessCombinationsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="BusinessCombinationsMember" xlink:title="definition: BusinessCombinationsDomain to BusinessCombinationsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ARTMSIncMember" xlink:label="ARTMSIncMember" xlink:title="ARTMSIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsMember" xlink:to="ARTMSIncMember" xlink:title="definition: BusinessCombinationsMember to ARTMSIncMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/AcquisitionsQsamBiosciencesIncDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfBusinessCombinationsLineItems" xlink:label="DisclosureOfBusinessCombinationsLineItems" xlink:title="DisclosureOfBusinessCombinationsLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AcquisitionAbstract" xlink:label="AcquisitionAbstract" xlink:title="AcquisitionAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AcquisitionAbstract" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AcquisitionAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AcquisitiondateFairValueOfFinalPurchasePriceConsideration" xlink:label="AcquisitiondateFairValueOfFinalPurchasePriceConsideration" xlink:title="AcquisitiondateFairValueOfFinalPurchasePriceConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AcquisitiondateFairValueOfFinalPurchasePriceConsideration" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AcquisitiondateFairValueOfFinalPurchasePriceConsideration" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfSharesOutstanding" xlink:label="NumberOfSharesOutstanding" xlink:title="NumberOfSharesOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="NumberOfSharesOutstanding" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to NumberOfSharesOutstanding" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ParValuePerShare" xlink:label="ParValuePerShare" xlink:title="ParValuePerShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="ParValuePerShare" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to ParValuePerShare" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesIncurred" xlink:label="LiabilitiesIncurred" xlink:title="LiabilitiesIncurred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="LiabilitiesIncurred" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to LiabilitiesIncurred" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" xlink:label="AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" xlink:title="AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AmountsRecognisedAsOfAcquisitionDateForEachMajorClassOfAssetsAcquiredAndLiabilitiesAssumedAbstract" xlink:label="AmountsRecognisedAsOfAcquisitionDateForEachMajorClassOfAssetsAcquiredAndLiabilitiesAssumedAbstract" xlink:title="AmountsRecognisedAsOfAcquisitionDateForEachMajorClassOfAssetsAcquiredAndLiabilitiesAssumedAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AmountsRecognisedAsOfAcquisitionDateForEachMajorClassOfAssetsAcquiredAndLiabilitiesAssumedAbstract" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AmountsRecognisedAsOfAcquisitionDateForEachMajorClassOfAssetsAcquiredAndLiabilitiesAssumedAbstract" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashAndCashEquivalentsRecognisedAsOfAcquisitionDate" xlink:label="CashAndCashEquivalentsRecognisedAsOfAcquisitionDate" xlink:title="CashAndCashEquivalentsRecognisedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="CashAndCashEquivalentsRecognisedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to CashAndCashEquivalentsRecognisedAsOfAcquisitionDate" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TradeAndOtherReceivablesRecognizedAsOfAcquisitionDate" xlink:label="TradeAndOtherReceivablesRecognizedAsOfAcquisitionDate" xlink:title="TradeAndOtherReceivablesRecognizedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="TradeAndOtherReceivablesRecognizedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to TradeAndOtherReceivablesRecognizedAsOfAcquisitionDate" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IdentifiableIntangibleAssetsRecognisedAsOfAcquisitionDate" xlink:label="IdentifiableIntangibleAssetsRecognisedAsOfAcquisitionDate" xlink:title="IdentifiableIntangibleAssetsRecognisedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="IdentifiableIntangibleAssetsRecognisedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to IdentifiableIntangibleAssetsRecognisedAsOfAcquisitionDate" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IdentifiableAssetsAcquiredLiabilitiesAssumed" xlink:label="IdentifiableAssetsAcquiredLiabilitiesAssumed" xlink:title="IdentifiableAssetsAcquiredLiabilitiesAssumed" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="IdentifiableAssetsAcquiredLiabilitiesAssumed" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to IdentifiableAssetsAcquiredLiabilitiesAssumed" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashTransferred" xlink:label="CashTransferred" xlink:title="CashTransferred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="CashTransferred" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to CashTransferred" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_EquityInterestsOfAcquirer" xlink:label="EquityInterestsOfAcquirer" xlink:title="EquityInterestsOfAcquirer" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="EquityInterestsOfAcquirer" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to EquityInterestsOfAcquirer" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PerformanceRightsIssuedAsOfAcquisitionDate" xlink:label="PerformanceRightsIssuedAsOfAcquisitionDate" xlink:title="PerformanceRightsIssuedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="PerformanceRightsIssuedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to PerformanceRightsIssuedAsOfAcquisitionDate" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AcquisitiondateFairValueOfTotalConsiderationTransferred" xlink:label="AcquisitiondateFairValueOfTotalConsiderationTransferred" xlink:title="AcquisitiondateFairValueOfTotalConsiderationTransferred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AcquisitiondateFairValueOfTotalConsiderationTransferred" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AcquisitiondateFairValueOfTotalConsiderationTransferred" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfBusinessCombinationsTable" xlink:label="DisclosureOfBusinessCombinationsTable" xlink:title="DisclosureOfBusinessCombinationsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="DisclosureOfBusinessCombinationsTable" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to DisclosureOfBusinessCombinationsTable" order="16.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsAxis" xlink:label="BusinessCombinationsAxis" xlink:title="BusinessCombinationsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfBusinessCombinationsTable" xlink:to="BusinessCombinationsAxis" xlink:title="definition: DisclosureOfBusinessCombinationsTable to BusinessCombinationsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain_2" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain_2" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsMember" xlink:label="BusinessCombinationsMember" xlink:title="BusinessCombinationsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="BusinessCombinationsMember" xlink:title="definition: BusinessCombinationsDomain to BusinessCombinationsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_QSAMBiosciencesIncMember" xlink:label="QSAMBiosciencesIncMember" xlink:title="QSAMBiosciencesIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsMember" xlink:to="QSAMBiosciencesIncMember" xlink:title="definition: BusinessCombinationsMember to QSAMBiosciencesIncMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/TradeAndOtherPayablesDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/BorrowingsBorrowingsDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/BorrowingsLendersDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:label="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:title="DisclosureOfDetailedInformationAboutBorrowingsLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_BorrowingsLenderAbstract" xlink:label="BorrowingsLenderAbstract" xlink:title="BorrowingsLenderAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="BorrowingsLenderAbstract" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to BorrowingsLenderAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_BorrowingsOverpayments" xlink:label="BorrowingsOverpayments" xlink:title="BorrowingsOverpayments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="BorrowingsOverpayments" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to BorrowingsOverpayments" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ShorttermBorrowings" xlink:label="ShorttermBorrowings" xlink:title="ShorttermBorrowings" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="ShorttermBorrowings" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to ShorttermBorrowings" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_NonCurrentBorrowingsOverpayments" xlink:label="NonCurrentBorrowingsOverpayments" xlink:title="NonCurrentBorrowingsOverpayments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="NonCurrentBorrowingsOverpayments" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to NonCurrentBorrowingsOverpayments" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_MaximumBorrowingsCapacity" xlink:label="MaximumBorrowingsCapacity" xlink:title="MaximumBorrowingsCapacity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="MaximumBorrowingsCapacity" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to MaximumBorrowingsCapacity" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsMaturity" xlink:label="BorrowingsMaturity" xlink:title="BorrowingsMaturity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="BorrowingsMaturity" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to BorrowingsMaturity" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:label="DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:title="DisclosureOfDetailedInformationAboutBorrowingsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to DisclosureOfDetailedInformationAboutBorrowingsTable" order="7.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameAxis" xlink:label="BorrowingsByNameAxis" xlink:title="BorrowingsByNameAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:to="BorrowingsByNameAxis" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsTable to BorrowingsByNameAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameDomain" xlink:label="BorrowingsByNameDomain" xlink:title="BorrowingsByNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BorrowingsByNameAxis" xlink:to="BorrowingsByNameDomain" xlink:title="definition: BorrowingsByNameAxis to BorrowingsByNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameDomain" xlink:label="BorrowingsByNameDomain_2" xlink:title="BorrowingsByNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BorrowingsByNameAxis" xlink:to="BorrowingsByNameDomain_2" xlink:title="definition: BorrowingsByNameAxis to BorrowingsByNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_JPMorganSecuritiesPlcAsTheManagerForConvertibleBondHoldersMember" xlink:label="JPMorganSecuritiesPlcAsTheManagerForConvertibleBondHoldersMember" xlink:title="JPMorganSecuritiesPlcAsTheManagerForConvertibleBondHoldersMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BorrowingsByNameDomain" xlink:to="JPMorganSecuritiesPlcAsTheManagerForConvertibleBondHoldersMember" xlink:title="definition: BorrowingsByNameDomain to JPMorganSecuritiesPlcAsTheManagerForConvertibleBondHoldersMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TheHongkongAndShanghaiBankingCorporationLimitedAsTheTrusteeForConvertibleBondHoldersMember" xlink:label="TheHongkongAndShanghaiBankingCorporationLimitedAsTheTrusteeForConvertibleBondHoldersMember" xlink:title="TheHongkongAndShanghaiBankingCorporationLimitedAsTheTrusteeForConvertibleBondHoldersMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BorrowingsByNameDomain" xlink:to="TheHongkongAndShanghaiBankingCorporationLimitedAsTheTrusteeForConvertibleBondHoldersMember" xlink:title="definition: BorrowingsByNameDomain to TheHongkongAndShanghaiBankingCorporationLimitedAsTheTrusteeForConvertibleBondHoldersMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IMBCGroupMember" xlink:label="IMBCGroupMember" xlink:title="IMBCGroupMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BorrowingsByNameDomain" xlink:to="IMBCGroupMember" xlink:title="definition: BorrowingsByNameDomain to IMBCGroupMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_BNPParibasMember" xlink:label="BNPParibasMember" xlink:title="BNPParibasMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BorrowingsByNameDomain" xlink:to="BNPParibasMember" xlink:title="definition: BorrowingsByNameDomain to BNPParibasMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_HSBCAustraliaLtdMember" xlink:label="HSBCAustraliaLtdMember" xlink:title="HSBCAustraliaLtdMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BorrowingsByNameDomain" xlink:to="HSBCAustraliaLtdMember" xlink:title="definition: BorrowingsByNameDomain to HSBCAustraliaLtdMember" order="5.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/BorrowingsBankLoansDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:label="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:title="DisclosureOfDetailedInformationAboutBorrowingsLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_BankLoansAbstract" xlink:label="BankLoansAbstract" xlink:title="BankLoansAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="BankLoansAbstract" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to BankLoansAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Borrowings" xlink:label="Borrowings" xlink:title="Borrowings" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="Borrowings" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to Borrowings" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_NumberOfLoanAgreements" xlink:label="NumberOfLoanAgreements" xlink:title="NumberOfLoanAgreements" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="NumberOfLoanAgreements" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to NumberOfLoanAgreements" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_BorrowingsMaturityTerm" xlink:label="BorrowingsMaturityTerm" xlink:title="BorrowingsMaturityTerm" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="BorrowingsMaturityTerm" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to BorrowingsMaturityTerm" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_LoanRepaymentPeriod" xlink:label="LoanRepaymentPeriod" xlink:title="LoanRepaymentPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="LoanRepaymentPeriod" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to LoanRepaymentPeriod" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UndrawnBorrowingFacilities" xlink:label="UndrawnBorrowingFacilities" xlink:title="UndrawnBorrowingFacilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="UndrawnBorrowingFacilities" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to UndrawnBorrowingFacilities" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_CapitalAndReservesPercentage" xlink:label="CapitalAndReservesPercentage" xlink:title="CapitalAndReservesPercentage" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="CapitalAndReservesPercentage" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to CapitalAndReservesPercentage" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:label="DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:title="DisclosureOfDetailedInformationAboutBorrowingsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to DisclosureOfDetailedInformationAboutBorrowingsTable" order="8.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProductsAndServicesAxis" xlink:label="ProductsAndServicesAxis" xlink:title="ProductsAndServicesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:to="ProductsAndServicesAxis" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsTable to ProductsAndServicesAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProductsAndServicesDomain" xlink:label="ProductsAndServicesDomain" xlink:title="ProductsAndServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ProductsAndServicesAxis" xlink:to="ProductsAndServicesDomain" xlink:title="definition: ProductsAndServicesAxis to ProductsAndServicesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProductsAndServicesDomain" xlink:label="ProductsAndServicesDomain_2" xlink:title="ProductsAndServicesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ProductsAndServicesAxis" xlink:to="ProductsAndServicesDomain_2" xlink:title="definition: ProductsAndServicesAxis to ProductsAndServicesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_RadiopharmaceuticalProductionFacilityMember" xlink:label="RadiopharmaceuticalProductionFacilityMember" xlink:title="RadiopharmaceuticalProductionFacilityMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ProductsAndServicesDomain" xlink:to="RadiopharmaceuticalProductionFacilityMember" xlink:title="definition: ProductsAndServicesDomain to RadiopharmaceuticalProductionFacilityMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameAxis" xlink:label="BorrowingsByNameAxis" xlink:title="BorrowingsByNameAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:to="BorrowingsByNameAxis" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsTable to BorrowingsByNameAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameDomain" xlink:label="BorrowingsByNameDomain" xlink:title="BorrowingsByNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BorrowingsByNameAxis" xlink:to="BorrowingsByNameDomain" xlink:title="definition: BorrowingsByNameAxis to BorrowingsByNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameDomain" xlink:label="BorrowingsByNameDomain_2" xlink:title="BorrowingsByNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BorrowingsByNameAxis" xlink:to="BorrowingsByNameDomain_2" xlink:title="definition: BorrowingsByNameAxis to BorrowingsByNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_BNPParibasAndIMBCGroupMember" xlink:label="BNPParibasAndIMBCGroupMember" xlink:title="BNPParibasAndIMBCGroupMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BorrowingsByNameDomain" xlink:to="BNPParibasAndIMBCGroupMember" xlink:title="definition: BorrowingsByNameDomain to BNPParibasAndIMBCGroupMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_BNPParibasMember" xlink:label="BNPParibasMember" xlink:title="BNPParibasMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BorrowingsByNameDomain" xlink:to="BNPParibasMember" xlink:title="definition: BorrowingsByNameDomain to BNPParibasMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:to="RangeAxis" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsTable to RangeAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="RangeDomain" xlink:title="RangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeDomain" xlink:title="definition: RangeAxis to RangeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="RangeDomain_2" xlink:title="RangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeDomain_2" xlink:title="definition: RangeAxis to RangeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TopOfRangeMember" xlink:label="TopOfRangeMember" xlink:title="TopOfRangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeDomain" xlink:to="TopOfRangeMember" xlink:title="definition: RangeDomain to TopOfRangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesArisingFromFinancingActivitiesAxis" xlink:label="LiabilitiesArisingFromFinancingActivitiesAxis" xlink:title="LiabilitiesArisingFromFinancingActivitiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:to="LiabilitiesArisingFromFinancingActivitiesAxis" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsTable to LiabilitiesArisingFromFinancingActivitiesAxis" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesArisingFromFinancingActivitiesDomain" xlink:label="LiabilitiesArisingFromFinancingActivitiesDomain" xlink:title="LiabilitiesArisingFromFinancingActivitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LiabilitiesArisingFromFinancingActivitiesAxis" xlink:to="LiabilitiesArisingFromFinancingActivitiesDomain" xlink:title="definition: LiabilitiesArisingFromFinancingActivitiesAxis to LiabilitiesArisingFromFinancingActivitiesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesArisingFromFinancingActivitiesDomain" xlink:label="LiabilitiesArisingFromFinancingActivitiesDomain_2" xlink:title="LiabilitiesArisingFromFinancingActivitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LiabilitiesArisingFromFinancingActivitiesAxis" xlink:to="LiabilitiesArisingFromFinancingActivitiesDomain_2" xlink:title="definition: LiabilitiesArisingFromFinancingActivitiesAxis to LiabilitiesArisingFromFinancingActivitiesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ConvertibleBondsMember" xlink:label="ConvertibleBondsMember" xlink:title="ConvertibleBondsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesArisingFromFinancingActivitiesDomain" xlink:to="ConvertibleBondsMember" xlink:title="definition: LiabilitiesArisingFromFinancingActivitiesDomain to ConvertibleBondsMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/BorrowingsWorkingCapitalFacilityDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:label="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:title="DisclosureOfDetailedInformationAboutBorrowingsLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_WorkingCapitalFacilityAbstract" xlink:label="WorkingCapitalFacilityAbstract" xlink:title="WorkingCapitalFacilityAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="WorkingCapitalFacilityAbstract" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to WorkingCapitalFacilityAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_MaximumBorrowingFacility" xlink:label="MaximumBorrowingFacility" xlink:title="MaximumBorrowingFacility" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="MaximumBorrowingFacility" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to MaximumBorrowingFacility" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingCostsIncurred" xlink:label="BorrowingCostsIncurred" xlink:title="BorrowingCostsIncurred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="BorrowingCostsIncurred" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to BorrowingCostsIncurred" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RestrictedCashAndCashEquivalents" xlink:label="RestrictedCashAndCashEquivalents" xlink:title="RestrictedCashAndCashEquivalents" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="RestrictedCashAndCashEquivalents" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to RestrictedCashAndCashEquivalents" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:label="DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:title="DisclosureOfDetailedInformationAboutBorrowingsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsLineItems" xlink:to="DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsLineItems to DisclosureOfDetailedInformationAboutBorrowingsTable" order="5.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameAxis" xlink:label="BorrowingsByNameAxis" xlink:title="BorrowingsByNameAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfDetailedInformationAboutBorrowingsTable" xlink:to="BorrowingsByNameAxis" xlink:title="definition: DisclosureOfDetailedInformationAboutBorrowingsTable to BorrowingsByNameAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameDomain" xlink:label="BorrowingsByNameDomain" xlink:title="BorrowingsByNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BorrowingsByNameAxis" xlink:to="BorrowingsByNameDomain" xlink:title="definition: BorrowingsByNameAxis to BorrowingsByNameDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsByNameDomain" xlink:label="BorrowingsByNameDomain_2" xlink:title="BorrowingsByNameDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BorrowingsByNameAxis" xlink:to="BorrowingsByNameDomain_2" xlink:title="definition: BorrowingsByNameAxis to BorrowingsByNameDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_HSBCBankAustraliaLimitedMember" xlink:label="HSBCBankAustraliaLimitedMember" xlink:title="HSBCBankAustraliaLimitedMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BorrowingsByNameDomain" xlink:to="HSBCBankAustraliaLimitedMember" xlink:title="definition: BorrowingsByNameDomain to HSBCBankAustraliaLimitedMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/BorrowingsConvertibleBondsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:label="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:title="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ConvertibleBondsAbstract" xlink:label="ConvertibleBondsAbstract" xlink:title="ConvertibleBondsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="ConvertibleBondsAbstract" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to ConvertibleBondsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BondsIssued" xlink:label="BondsIssued" xlink:title="BondsIssued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="BondsIssued" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to BondsIssued" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ConvertibleBondsMaturityYear" xlink:label="ConvertibleBondsMaturityYear" xlink:title="ConvertibleBondsMaturityYear" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="ConvertibleBondsMaturityYear" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to ConvertibleBondsMaturityYear" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ConversionPrice" xlink:label="ConversionPrice" xlink:title="ConversionPrice" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="ConversionPrice" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to ConversionPrice" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProceedsFromIssueOfBondsNotesAndDebentures" xlink:label="ProceedsFromIssueOfBondsNotesAndDebentures" xlink:title="ProceedsFromIssueOfBondsNotesAndDebentures" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="ProceedsFromIssueOfBondsNotesAndDebentures" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to ProceedsFromIssueOfBondsNotesAndDebentures" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsInterestRate" xlink:label="BorrowingsInterestRate" xlink:title="BorrowingsInterestRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="BorrowingsInterestRate" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to BorrowingsInterestRate" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_BorrowingInterestFrequencyOfPeriodicPayment" xlink:label="BorrowingInterestFrequencyOfPeriodicPayment" xlink:title="BorrowingInterestFrequencyOfPeriodicPayment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="BorrowingInterestFrequencyOfPeriodicPayment" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to BorrowingInterestFrequencyOfPeriodicPayment" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BorrowingsMaturity" xlink:label="BorrowingsMaturity" xlink:title="BorrowingsMaturity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="BorrowingsMaturity" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to BorrowingsMaturity" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_FaceValueOfConvertibleBondsIssued" xlink:label="FaceValueOfConvertibleBondsIssued" xlink:title="FaceValueOfConvertibleBondsIssued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="FaceValueOfConvertibleBondsIssued" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to FaceValueOfConvertibleBondsIssued" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PaymentsForDebtIssueCosts" xlink:label="PaymentsForDebtIssueCosts" xlink:title="PaymentsForDebtIssueCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="PaymentsForDebtIssueCosts" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to PaymentsForDebtIssueCosts" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_OtherEquitySecuritiesValueOfConversionRights" xlink:label="OtherEquitySecuritiesValueOfConversionRights" xlink:title="OtherEquitySecuritiesValueOfConversionRights" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="OtherEquitySecuritiesValueOfConversionRights" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to OtherEquitySecuritiesValueOfConversionRights" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_UnwindOfDiscount" xlink:label="UnwindOfDiscount" xlink:title="UnwindOfDiscount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="UnwindOfDiscount" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to UnwindOfDiscount" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_InterestExpenseOnBonds" xlink:label="InterestExpenseOnBonds" xlink:title="InterestExpenseOnBonds" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="InterestExpenseOnBonds" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to InterestExpenseOnBonds" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_InterestPaidOnConvertibleBondsClassifiedAsOperatingActivities" xlink:label="InterestPaidOnConvertibleBondsClassifiedAsOperatingActivities" xlink:title="InterestPaidOnConvertibleBondsClassifiedAsOperatingActivities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="InterestPaidOnConvertibleBondsClassifiedAsOperatingActivities" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to InterestPaidOnConvertibleBondsClassifiedAsOperatingActivities" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughConversionOfConvertibleInstruments" xlink:label="IncreaseDecreaseThroughConversionOfConvertibleInstruments" xlink:title="IncreaseDecreaseThroughConversionOfConvertibleInstruments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="IncreaseDecreaseThroughConversionOfConvertibleInstruments" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to IncreaseDecreaseThroughConversionOfConvertibleInstruments" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ShorttermBorrowings" xlink:label="ShorttermBorrowings" xlink:title="ShorttermBorrowings" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="ShorttermBorrowings" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to ShorttermBorrowings" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LongtermBorrowings" xlink:label="LongtermBorrowings" xlink:title="LongtermBorrowings" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="LongtermBorrowings" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to LongtermBorrowings" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesArisingFromFinancingActivities" xlink:label="LiabilitiesArisingFromFinancingActivities" xlink:title="LiabilitiesArisingFromFinancingActivities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="LiabilitiesArisingFromFinancingActivities" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to LiabilitiesArisingFromFinancingActivities" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Borrowings" xlink:label="Borrowings" xlink:title="Borrowings" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="Borrowings" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to Borrowings" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinancialLiabilitiesAtFairValue" xlink:label="FinancialLiabilitiesAtFairValue" xlink:title="FinancialLiabilitiesAtFairValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="FinancialLiabilitiesAtFairValue" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to FinancialLiabilitiesAtFairValue" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable" xlink:label="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable" xlink:title="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable" order="21.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesArisingFromFinancingActivitiesAxis" xlink:label="LiabilitiesArisingFromFinancingActivitiesAxis" xlink:title="LiabilitiesArisingFromFinancingActivitiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable" xlink:to="LiabilitiesArisingFromFinancingActivitiesAxis" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable to LiabilitiesArisingFromFinancingActivitiesAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesArisingFromFinancingActivitiesDomain" xlink:label="LiabilitiesArisingFromFinancingActivitiesDomain" xlink:title="LiabilitiesArisingFromFinancingActivitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LiabilitiesArisingFromFinancingActivitiesAxis" xlink:to="LiabilitiesArisingFromFinancingActivitiesDomain" xlink:title="definition: LiabilitiesArisingFromFinancingActivitiesAxis to LiabilitiesArisingFromFinancingActivitiesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesArisingFromFinancingActivitiesDomain" xlink:label="LiabilitiesArisingFromFinancingActivitiesDomain_2" xlink:title="LiabilitiesArisingFromFinancingActivitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LiabilitiesArisingFromFinancingActivitiesAxis" xlink:to="LiabilitiesArisingFromFinancingActivitiesDomain_2" xlink:title="definition: LiabilitiesArisingFromFinancingActivitiesAxis to LiabilitiesArisingFromFinancingActivitiesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_BankLoansMember" xlink:label="BankLoansMember" xlink:title="BankLoansMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesArisingFromFinancingActivitiesDomain" xlink:to="BankLoansMember" xlink:title="definition: LiabilitiesArisingFromFinancingActivitiesDomain to BankLoansMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ConvertibleBondsMember" xlink:label="ConvertibleBondsMember" xlink:title="ConvertibleBondsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesArisingFromFinancingActivitiesDomain" xlink:to="ConvertibleBondsMember" xlink:title="definition: LiabilitiesArisingFromFinancingActivitiesDomain to ConvertibleBondsMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/BorrowingsReconciliationOfLiabilitiesArisingFromFinancingActivitiesDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:label="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:title="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_CapitalRiskManagementAbstract" xlink:label="CapitalRiskManagementAbstract" xlink:title="CapitalRiskManagementAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="CapitalRiskManagementAbstract" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to CapitalRiskManagementAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesAbstract" xlink:label="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesAbstract" xlink:title="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesAbstract" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesArisingFromFinancingActivities" xlink:label="LiabilitiesArisingFromFinancingActivities" xlink:title="LiabilitiesArisingFromFinancingActivities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="LiabilitiesArisingFromFinancingActivities" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to LiabilitiesArisingFromFinancingActivities" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughFinancingCashFlowsLiabilitiesArisingFromFinancingActivities" xlink:label="IncreaseDecreaseThroughFinancingCashFlowsLiabilitiesArisingFromFinancingActivities" xlink:title="IncreaseDecreaseThroughFinancingCashFlowsLiabilitiesArisingFromFinancingActivities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="IncreaseDecreaseThroughFinancingCashFlowsLiabilitiesArisingFromFinancingActivities" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to IncreaseDecreaseThroughFinancingCashFlowsLiabilitiesArisingFromFinancingActivities" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughOtherChangesLiabilitiesArisingFromFinancingActivities" xlink:label="IncreaseDecreaseThroughOtherChangesLiabilitiesArisingFromFinancingActivities" xlink:title="IncreaseDecreaseThroughOtherChangesLiabilitiesArisingFromFinancingActivities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="IncreaseDecreaseThroughOtherChangesLiabilitiesArisingFromFinancingActivities" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to IncreaseDecreaseThroughOtherChangesLiabilitiesArisingFromFinancingActivities" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_LeverageRatio" xlink:label="LeverageRatio" xlink:title="LeverageRatio" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="LeverageRatio" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to LeverageRatio" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable" xlink:label="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable" xlink:title="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems" xlink:to="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesLineItems to DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable" order="7.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesArisingFromFinancingActivitiesAxis" xlink:label="LiabilitiesArisingFromFinancingActivitiesAxis" xlink:title="LiabilitiesArisingFromFinancingActivitiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable" xlink:to="LiabilitiesArisingFromFinancingActivitiesAxis" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable to LiabilitiesArisingFromFinancingActivitiesAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesArisingFromFinancingActivitiesDomain" xlink:label="LiabilitiesArisingFromFinancingActivitiesDomain" xlink:title="LiabilitiesArisingFromFinancingActivitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LiabilitiesArisingFromFinancingActivitiesAxis" xlink:to="LiabilitiesArisingFromFinancingActivitiesDomain" xlink:title="definition: LiabilitiesArisingFromFinancingActivitiesAxis to LiabilitiesArisingFromFinancingActivitiesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesArisingFromFinancingActivitiesDomain" xlink:label="LiabilitiesArisingFromFinancingActivitiesDomain_2" xlink:title="LiabilitiesArisingFromFinancingActivitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LiabilitiesArisingFromFinancingActivitiesAxis" xlink:to="LiabilitiesArisingFromFinancingActivitiesDomain_2" xlink:title="definition: LiabilitiesArisingFromFinancingActivitiesAxis to LiabilitiesArisingFromFinancingActivitiesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_BankLoansMember" xlink:label="BankLoansMember" xlink:title="BankLoansMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesArisingFromFinancingActivitiesDomain" xlink:to="BankLoansMember" xlink:title="definition: LiabilitiesArisingFromFinancingActivitiesDomain to BankLoansMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ConvertibleBondsMember" xlink:label="ConvertibleBondsMember" xlink:title="ConvertibleBondsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesArisingFromFinancingActivitiesDomain" xlink:to="ConvertibleBondsMember" xlink:title="definition: LiabilitiesArisingFromFinancingActivitiesDomain to ConvertibleBondsMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LeaseLiabilitiesMember" xlink:label="LeaseLiabilitiesMember" xlink:title="LeaseLiabilitiesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LiabilitiesArisingFromFinancingActivitiesDomain" xlink:to="LeaseLiabilitiesMember" xlink:title="definition: LiabilitiesArisingFromFinancingActivitiesDomain to LeaseLiabilitiesMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable" xlink:to="RangeAxis" xlink:title="definition: DisclosureOfReconciliationOfLiabilitiesArisingFromFinancingActivitiesTable to RangeAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="RangeDomain" xlink:title="RangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeDomain" xlink:title="definition: RangeAxis to RangeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="RangeDomain_2" xlink:title="RangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeDomain_2" xlink:title="definition: RangeAxis to RangeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TopOfRangeMember" xlink:label="TopOfRangeMember" xlink:title="TopOfRangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeDomain" xlink:to="TopOfRangeMember" xlink:title="definition: RangeDomain to TopOfRangeMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ContractLiabilitiesLiabilitiesRelatedToContractsWithCustomersDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ContractLiabilitiesGrandPharmaStrategicPartnershipDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:label="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:title="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrandPharmaStrategicPartnershipAbstract" xlink:label="GrandPharmaStrategicPartnershipAbstract" xlink:title="GrandPharmaStrategicPartnershipAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:to="GrandPharmaStrategicPartnershipAbstract" xlink:title="definition: DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems to GrandPharmaStrategicPartnershipAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_NonRefundableUpfrontPaymentReceived" xlink:label="NonRefundableUpfrontPaymentReceived" xlink:title="NonRefundableUpfrontPaymentReceived" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:to="NonRefundableUpfrontPaymentReceived" xlink:title="definition: DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems to NonRefundableUpfrontPaymentReceived" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable" xlink:label="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable" xlink:title="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems" xlink:to="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable" xlink:title="definition: DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersLineItems to DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfContractsAxis" xlink:label="TypesOfContractsAxis" xlink:title="TypesOfContractsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable" xlink:to="TypesOfContractsAxis" xlink:title="definition: DisclosureOfDisaggregationOfRevenueFromContractsWithCustomersTable to TypesOfContractsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfContractsDomain" xlink:label="TypesOfContractsDomain" xlink:title="TypesOfContractsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TypesOfContractsAxis" xlink:to="TypesOfContractsDomain" xlink:title="definition: TypesOfContractsAxis to TypesOfContractsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfContractsDomain" xlink:label="TypesOfContractsDomain_2" xlink:title="TypesOfContractsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TypesOfContractsAxis" xlink:to="TypesOfContractsDomain_2" xlink:title="definition: TypesOfContractsAxis to TypesOfContractsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrandPharmaceuticalGroupLimitedMember" xlink:label="GrandPharmaceuticalGroupLimitedMember" xlink:title="GrandPharmaceuticalGroupLimitedMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TypesOfContractsDomain" xlink:to="GrandPharmaceuticalGroupLimitedMember" xlink:title="definition: TypesOfContractsDomain to GrandPharmaceuticalGroupLimitedMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ContractLiabilitiesWalloonRegionNonreimbursableGrantDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/LeaseLiabilitiesLeasePaymentsDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/LeaseLiabilitiesLeaseLiabilitiesDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/LeaseLiabilitiesInterestExpenseRelatingToLeasesDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:label="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:title="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_InterestExpenseRelatingToLeasesAbstract" xlink:label="InterestExpenseRelatingToLeasesAbstract" xlink:title="InterestExpenseRelatingToLeasesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="InterestExpenseRelatingToLeasesAbstract" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems to InterestExpenseRelatingToLeasesAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PaymentsOfLeaseLiabilitiesClassifiedAsFinancingActivities" xlink:label="PaymentsOfLeaseLiabilitiesClassifiedAsFinancingActivities" xlink:title="PaymentsOfLeaseLiabilitiesClassifiedAsFinancingActivities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="PaymentsOfLeaseLiabilitiesClassifiedAsFinancingActivities" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems to PaymentsOfLeaseLiabilitiesClassifiedAsFinancingActivities" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_InterestExpenseOnLeaseLiabilities" xlink:label="InterestExpenseOnLeaseLiabilities" xlink:title="InterestExpenseOnLeaseLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="InterestExpenseOnLeaseLiabilities" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems to InterestExpenseOnLeaseLiabilities" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" xlink:label="DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" xlink:title="DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems" xlink:to="DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsLineItems to DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" order="4.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfAssetsAxis" xlink:label="ClassesOfAssetsAxis" xlink:title="ClassesOfAssetsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable" xlink:to="ClassesOfAssetsAxis" xlink:title="definition: DisclosureOfQuantitativeInformationAboutRightofuseAssetsTable to ClassesOfAssetsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfAssetsDomain" xlink:label="ClassesOfAssetsDomain" xlink:title="ClassesOfAssetsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ClassesOfAssetsAxis" xlink:to="ClassesOfAssetsDomain" xlink:title="definition: ClassesOfAssetsAxis to ClassesOfAssetsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfAssetsDomain" xlink:label="ClassesOfAssetsDomain_2" xlink:title="ClassesOfAssetsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassesOfAssetsAxis" xlink:to="ClassesOfAssetsDomain_2" xlink:title="definition: ClassesOfAssetsAxis to ClassesOfAssetsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LandAndBuildingsMember" xlink:label="LandAndBuildingsMember" xlink:title="LandAndBuildingsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfAssetsDomain" xlink:to="LandAndBuildingsMember" xlink:title="definition: ClassesOfAssetsDomain to LandAndBuildingsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MotorVehiclesMember" xlink:label="MotorVehiclesMember" xlink:title="MotorVehiclesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfAssetsDomain" xlink:to="MotorVehiclesMember" xlink:title="definition: ClassesOfAssetsDomain to MotorVehiclesMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ProvisionsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOtherProvisionsLineItems" xlink:label="DisclosureOfOtherProvisionsLineItems" xlink:title="DisclosureOfOtherProvisionsLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ReconciliationOfChangesInOtherProvisionsAbstract" xlink:label="ReconciliationOfChangesInOtherProvisionsAbstract" xlink:title="ReconciliationOfChangesInOtherProvisionsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOtherProvisionsLineItems" xlink:to="ReconciliationOfChangesInOtherProvisionsAbstract" xlink:title="definition: DisclosureOfOtherProvisionsLineItems to ReconciliationOfChangesInOtherProvisionsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Provisions" xlink:label="Provisions" xlink:title="Provisions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOtherProvisionsLineItems" xlink:to="Provisions" xlink:title="definition: DisclosureOfOtherProvisionsLineItems to Provisions" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseThroughRemeasurementOfOtherProvisions" xlink:label="IncreaseDecreaseThroughRemeasurementOfOtherProvisions" xlink:title="IncreaseDecreaseThroughRemeasurementOfOtherProvisions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOtherProvisionsLineItems" xlink:to="IncreaseDecreaseThroughRemeasurementOfOtherProvisions" xlink:title="definition: DisclosureOfOtherProvisionsLineItems to IncreaseDecreaseThroughRemeasurementOfOtherProvisions" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughChangeInDiscountRateOtherProvisions" xlink:label="IncreaseDecreaseThroughChangeInDiscountRateOtherProvisions" xlink:title="IncreaseDecreaseThroughChangeInDiscountRateOtherProvisions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOtherProvisionsLineItems" xlink:to="IncreaseDecreaseThroughChangeInDiscountRateOtherProvisions" xlink:title="definition: DisclosureOfOtherProvisionsLineItems to IncreaseDecreaseThroughChangeInDiscountRateOtherProvisions" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_OtherProvisionsChargedToProfitLoss" xlink:label="OtherProvisionsChargedToProfitLoss" xlink:title="OtherProvisionsChargedToProfitLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOtherProvisionsLineItems" xlink:to="OtherProvisionsChargedToProfitLoss" xlink:title="definition: DisclosureOfOtherProvisionsLineItems to OtherProvisionsChargedToProfitLoss" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughNetExchangeDifferencesOtherProvisions" xlink:label="IncreaseDecreaseThroughNetExchangeDifferencesOtherProvisions" xlink:title="IncreaseDecreaseThroughNetExchangeDifferencesOtherProvisions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOtherProvisionsLineItems" xlink:to="IncreaseDecreaseThroughNetExchangeDifferencesOtherProvisions" xlink:title="definition: DisclosureOfOtherProvisionsLineItems to IncreaseDecreaseThroughNetExchangeDifferencesOtherProvisions" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AcquisitionsThroughBusinessCombinationsOtherProvisions" xlink:label="AcquisitionsThroughBusinessCombinationsOtherProvisions" xlink:title="AcquisitionsThroughBusinessCombinationsOtherProvisions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOtherProvisionsLineItems" xlink:to="AcquisitionsThroughBusinessCombinationsOtherProvisions" xlink:title="definition: DisclosureOfOtherProvisionsLineItems to AcquisitionsThroughBusinessCombinationsOtherProvisions" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseInOtherProvisionAdjustedToPropertyPlantAndEquipment" xlink:label="IncreaseDecreaseInOtherProvisionAdjustedToPropertyPlantAndEquipment" xlink:title="IncreaseDecreaseInOtherProvisionAdjustedToPropertyPlantAndEquipment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOtherProvisionsLineItems" xlink:to="IncreaseDecreaseInOtherProvisionAdjustedToPropertyPlantAndEquipment" xlink:title="definition: DisclosureOfOtherProvisionsLineItems to IncreaseDecreaseInOtherProvisionAdjustedToPropertyPlantAndEquipment" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseInOtherProvisionAdjustedToIntangibleAssets" xlink:label="IncreaseDecreaseInOtherProvisionAdjustedToIntangibleAssets" xlink:title="IncreaseDecreaseInOtherProvisionAdjustedToIntangibleAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOtherProvisionsLineItems" xlink:to="IncreaseDecreaseInOtherProvisionAdjustedToIntangibleAssets" xlink:title="definition: DisclosureOfOtherProvisionsLineItems to IncreaseDecreaseInOtherProvisionAdjustedToIntangibleAssets" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProvisionUsedOtherProvisions" xlink:label="ProvisionUsedOtherProvisions" xlink:title="ProvisionUsedOtherProvisions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOtherProvisionsLineItems" xlink:to="ProvisionUsedOtherProvisions" xlink:title="definition: DisclosureOfOtherProvisionsLineItems to ProvisionUsedOtherProvisions" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrentProvisions" xlink:label="CurrentProvisions" xlink:title="CurrentProvisions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOtherProvisionsLineItems" xlink:to="CurrentProvisions" xlink:title="definition: DisclosureOfOtherProvisionsLineItems to CurrentProvisions" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NoncurrentProvisions" xlink:label="NoncurrentProvisions" xlink:title="NoncurrentProvisions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOtherProvisionsLineItems" xlink:to="NoncurrentProvisions" xlink:title="definition: DisclosureOfOtherProvisionsLineItems to NoncurrentProvisions" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_RiskAdjustedDiscountRate" xlink:label="RiskAdjustedDiscountRate" xlink:title="RiskAdjustedDiscountRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOtherProvisionsLineItems" xlink:to="RiskAdjustedDiscountRate" xlink:title="definition: DisclosureOfOtherProvisionsLineItems to RiskAdjustedDiscountRate" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DecommissioningCostsExpectedToBeIncurred" xlink:label="DecommissioningCostsExpectedToBeIncurred" xlink:title="DecommissioningCostsExpectedToBeIncurred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOtherProvisionsLineItems" xlink:to="DecommissioningCostsExpectedToBeIncurred" xlink:title="definition: DisclosureOfOtherProvisionsLineItems to DecommissioningCostsExpectedToBeIncurred" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_RiskFreeRate" xlink:label="RiskFreeRate" xlink:title="RiskFreeRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfOtherProvisionsLineItems" xlink:to="RiskFreeRate" xlink:title="definition: DisclosureOfOtherProvisionsLineItems to RiskFreeRate" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfOtherProvisionsTable" xlink:label="DisclosureOfOtherProvisionsTable" xlink:title="DisclosureOfOtherProvisionsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfOtherProvisionsLineItems" xlink:to="DisclosureOfOtherProvisionsTable" xlink:title="definition: DisclosureOfOtherProvisionsLineItems to DisclosureOfOtherProvisionsTable" order="16.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CategoriesOfFinancialLiabilitiesAxis" xlink:label="CategoriesOfFinancialLiabilitiesAxis" xlink:title="CategoriesOfFinancialLiabilitiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfOtherProvisionsTable" xlink:to="CategoriesOfFinancialLiabilitiesAxis" xlink:title="definition: DisclosureOfOtherProvisionsTable to CategoriesOfFinancialLiabilitiesAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CategoriesOfFinancialLiabilitiesDomain" xlink:label="CategoriesOfFinancialLiabilitiesDomain" xlink:title="CategoriesOfFinancialLiabilitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="CategoriesOfFinancialLiabilitiesAxis" xlink:to="CategoriesOfFinancialLiabilitiesDomain" xlink:title="definition: CategoriesOfFinancialLiabilitiesAxis to CategoriesOfFinancialLiabilitiesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CategoriesOfFinancialLiabilitiesDomain" xlink:label="CategoriesOfFinancialLiabilitiesDomain_2" xlink:title="CategoriesOfFinancialLiabilitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="CategoriesOfFinancialLiabilitiesAxis" xlink:to="CategoriesOfFinancialLiabilitiesDomain_2" xlink:title="definition: CategoriesOfFinancialLiabilitiesAxis to CategoriesOfFinancialLiabilitiesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GovernmentGrantLiabilityMember" xlink:label="GovernmentGrantLiabilityMember" xlink:title="GovernmentGrantLiabilityMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CategoriesOfFinancialLiabilitiesDomain" xlink:to="GovernmentGrantLiabilityMember" xlink:title="definition: CategoriesOfFinancialLiabilitiesDomain to GovernmentGrantLiabilityMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DecommissioningLiabilityMember" xlink:label="DecommissioningLiabilityMember" xlink:title="DecommissioningLiabilityMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CategoriesOfFinancialLiabilitiesDomain" xlink:to="DecommissioningLiabilityMember" xlink:title="definition: CategoriesOfFinancialLiabilitiesDomain to DecommissioningLiabilityMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ContingentConsiderationContingentConsiderationDetails">
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DetailedInformationAboutContingentConsiderationLineItems" xlink:label="DetailedInformationAboutContingentConsiderationLineItems" xlink:title="DetailedInformationAboutContingentConsiderationLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DetailedInformationAboutContingentConsiderationAbstract" xlink:label="DetailedInformationAboutContingentConsiderationAbstract" xlink:title="DetailedInformationAboutContingentConsiderationAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="DetailedInformationAboutContingentConsiderationAbstract" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to DetailedInformationAboutContingentConsiderationAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ContingentConsideration" xlink:label="ContingentConsideration" xlink:title="ContingentConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="ContingentConsideration" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to ContingentConsideration" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_RemeasurementOfContingentConsideration" xlink:label="RemeasurementOfContingentConsideration" xlink:title="RemeasurementOfContingentConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="RemeasurementOfContingentConsideration" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to RemeasurementOfContingentConsideration" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ContingentConsiderationAmountOfUnwindDiscount" xlink:label="ContingentConsiderationAmountOfUnwindDiscount" xlink:title="ContingentConsiderationAmountOfUnwindDiscount" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="ContingentConsiderationAmountOfUnwindDiscount" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to ContingentConsiderationAmountOfUnwindDiscount" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ContingentConsiderationChargedToProfitOrLoss" xlink:label="ContingentConsiderationChargedToProfitOrLoss" xlink:title="ContingentConsiderationChargedToProfitOrLoss" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="ContingentConsiderationChargedToProfitOrLoss" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to ContingentConsiderationChargedToProfitOrLoss" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ContingentConsiderationAmountOfExchangeDifferences" xlink:label="ContingentConsiderationAmountOfExchangeDifferences" xlink:title="ContingentConsiderationAmountOfExchangeDifferences" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="ContingentConsiderationAmountOfExchangeDifferences" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to ContingentConsiderationAmountOfExchangeDifferences" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_BusinessAcquisitionContingentConsiderationTransferred" xlink:label="BusinessAcquisitionContingentConsiderationTransferred" xlink:title="BusinessAcquisitionContingentConsiderationTransferred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="BusinessAcquisitionContingentConsiderationTransferred" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to BusinessAcquisitionContingentConsiderationTransferred" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ContingentConsiderationAmountsAdjustedToIntangibleAssets" xlink:label="ContingentConsiderationAmountsAdjustedToIntangibleAssets" xlink:title="ContingentConsiderationAmountsAdjustedToIntangibleAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="ContingentConsiderationAmountsAdjustedToIntangibleAssets" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to ContingentConsiderationAmountsAdjustedToIntangibleAssets" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PaymentsForContingentConsiderationClassifiedAsOperatingAndInvestingActivities" xlink:label="PaymentsForContingentConsiderationClassifiedAsOperatingAndInvestingActivities" xlink:title="PaymentsForContingentConsiderationClassifiedAsOperatingAndInvestingActivities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="PaymentsForContingentConsiderationClassifiedAsOperatingAndInvestingActivities" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to PaymentsForContingentConsiderationClassifiedAsOperatingAndInvestingActivities" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_CurrentContingentConsideration" xlink:label="CurrentContingentConsideration" xlink:title="CurrentContingentConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="CurrentContingentConsideration" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to CurrentContingentConsideration" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_NonCurrentContingentConsideration" xlink:label="NonCurrentContingentConsideration" xlink:title="NonCurrentContingentConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="NonCurrentContingentConsideration" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to NonCurrentContingentConsideration" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DetailedInformationAboutContingentConsiderationTable" xlink:label="DetailedInformationAboutContingentConsiderationTable" xlink:title="DetailedInformationAboutContingentConsiderationTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="DetailedInformationAboutContingentConsiderationTable" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to DetailedInformationAboutContingentConsiderationTable" order="12.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsAxis" xlink:label="BusinessCombinationsAxis" xlink:title="BusinessCombinationsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DetailedInformationAboutContingentConsiderationTable" xlink:to="BusinessCombinationsAxis" xlink:title="definition: DetailedInformationAboutContingentConsiderationTable to BusinessCombinationsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain_2" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain_2" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ANMIMember" xlink:label="ANMIMember" xlink:title="ANMIMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="ANMIMember" xlink:title="definition: BusinessCombinationsDomain to ANMIMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TheraPharmMember" xlink:label="TheraPharmMember" xlink:title="TheraPharmMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="TheraPharmMember" xlink:title="definition: BusinessCombinationsDomain to TheraPharmMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_OptimalTracersMember" xlink:label="OptimalTracersMember" xlink:title="OptimalTracersMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="OptimalTracersMember" xlink:title="definition: BusinessCombinationsDomain to OptimalTracersMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IsoTherapeuticsGroupLLCMember" xlink:label="IsoTherapeuticsGroupLLCMember" xlink:title="IsoTherapeuticsGroupLLCMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="IsoTherapeuticsGroupLLCMember" xlink:title="definition: BusinessCombinationsDomain to IsoTherapeuticsGroupLLCMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ARTMSIncMember" xlink:label="ARTMSIncMember" xlink:title="ARTMSIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="ARTMSIncMember" xlink:title="definition: BusinessCombinationsDomain to ARTMSIncMember" order="5.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ContingentConsiderationTelixInnovationsTelixSwitzerlandAndTelixOptimalTracersDetails">
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DetailedInformationAboutContingentConsiderationLineItems" xlink:label="DetailedInformationAboutContingentConsiderationLineItems" xlink:title="DetailedInformationAboutContingentConsiderationLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_FutureVariablePayments" xlink:label="FutureVariablePayments" xlink:title="FutureVariablePayments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="FutureVariablePayments" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to FutureVariablePayments" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_OptionToBuyOutRemainingFutureVariablePayments" xlink:label="OptionToBuyOutRemainingFutureVariablePayments" xlink:title="OptionToBuyOutRemainingFutureVariablePayments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="OptionToBuyOutRemainingFutureVariablePayments" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to OptionToBuyOutRemainingFutureVariablePayments" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_RiskAdjustedPostTaxDiscountRate" xlink:label="RiskAdjustedPostTaxDiscountRate" xlink:title="RiskAdjustedPostTaxDiscountRate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="RiskAdjustedPostTaxDiscountRate" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to RiskAdjustedPostTaxDiscountRate" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AmountOfIncreaseDecreaseInPostTaxDiscountRateWouldDecreaseIncreaseContingentConsideration" xlink:label="AmountOfIncreaseDecreaseInPostTaxDiscountRateWouldDecreaseIncreaseContingentConsideration" xlink:title="AmountOfIncreaseDecreaseInPostTaxDiscountRateWouldDecreaseIncreaseContingentConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="AmountOfIncreaseDecreaseInPostTaxDiscountRateWouldDecreaseIncreaseContingentConsideration" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to AmountOfIncreaseDecreaseInPostTaxDiscountRateWouldDecreaseIncreaseContingentConsideration" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AmountOfIncreaseDecreaseInSalesVolumesWouldIncreaseDecreaseContingentConsideration" xlink:label="AmountOfIncreaseDecreaseInSalesVolumesWouldIncreaseDecreaseContingentConsideration" xlink:title="AmountOfIncreaseDecreaseInSalesVolumesWouldIncreaseDecreaseContingentConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="AmountOfIncreaseDecreaseInSalesVolumesWouldIncreaseDecreaseContingentConsideration" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to AmountOfIncreaseDecreaseInSalesVolumesWouldIncreaseDecreaseContingentConsideration" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AmountOfIncreaseDecreaseInNetSalesPricePerUnitWouldIncreaseDecreaseContingentConsideration" xlink:label="AmountOfIncreaseDecreaseInNetSalesPricePerUnitWouldIncreaseDecreaseContingentConsideration" xlink:title="AmountOfIncreaseDecreaseInNetSalesPricePerUnitWouldIncreaseDecreaseContingentConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="AmountOfIncreaseDecreaseInNetSalesPricePerUnitWouldIncreaseDecreaseContingentConsideration" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to AmountOfIncreaseDecreaseInNetSalesPricePerUnitWouldIncreaseDecreaseContingentConsideration" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AmountOfIncreaseDecreaseInProbabilityOfSuccessFactorWouldIncreaseDecreaseContingentConsideration" xlink:label="AmountOfIncreaseDecreaseInProbabilityOfSuccessFactorWouldIncreaseDecreaseContingentConsideration" xlink:title="AmountOfIncreaseDecreaseInProbabilityOfSuccessFactorWouldIncreaseDecreaseContingentConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="AmountOfIncreaseDecreaseInProbabilityOfSuccessFactorWouldIncreaseDecreaseContingentConsideration" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to AmountOfIncreaseDecreaseInProbabilityOfSuccessFactorWouldIncreaseDecreaseContingentConsideration" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_MilestonePaymentOnCompletionOfPhaseIIIPivotalRegistrationTrial" xlink:label="MilestonePaymentOnCompletionOfPhaseIIIPivotalRegistrationTrial" xlink:title="MilestonePaymentOnCompletionOfPhaseIIIPivotalRegistrationTrial" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="MilestonePaymentOnCompletionOfPhaseIIIPivotalRegistrationTrial" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to MilestonePaymentOnCompletionOfPhaseIIIPivotalRegistrationTrial" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_MilestonePaymentOnReceiptOfSecondMarketingApproval" xlink:label="MilestonePaymentOnReceiptOfSecondMarketingApproval" xlink:title="MilestonePaymentOnReceiptOfSecondMarketingApproval" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="MilestonePaymentOnReceiptOfSecondMarketingApproval" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to MilestonePaymentOnReceiptOfSecondMarketingApproval" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PercentageOfNetSales" xlink:label="PercentageOfNetSales" xlink:title="PercentageOfNetSales" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="PercentageOfNetSales" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to PercentageOfNetSales" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DetailedInformationAboutContingentConsiderationTable" xlink:label="DetailedInformationAboutContingentConsiderationTable" xlink:title="DetailedInformationAboutContingentConsiderationTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DetailedInformationAboutContingentConsiderationLineItems" xlink:to="DetailedInformationAboutContingentConsiderationTable" xlink:title="definition: DetailedInformationAboutContingentConsiderationLineItems to DetailedInformationAboutContingentConsiderationTable" order="11.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsAxis" xlink:label="BusinessCombinationsAxis" xlink:title="BusinessCombinationsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DetailedInformationAboutContingentConsiderationTable" xlink:to="BusinessCombinationsAxis" xlink:title="definition: DetailedInformationAboutContingentConsiderationTable to BusinessCombinationsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain_2" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain_2" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ANMIMember" xlink:label="ANMIMember" xlink:title="ANMIMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="ANMIMember" xlink:title="definition: BusinessCombinationsDomain to ANMIMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TheraPharmMember" xlink:label="TheraPharmMember" xlink:title="TheraPharmMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="TheraPharmMember" xlink:title="definition: BusinessCombinationsDomain to TheraPharmMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UnobservableInputsAxis" xlink:label="UnobservableInputsAxis" xlink:title="UnobservableInputsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DetailedInformationAboutContingentConsiderationTable" xlink:to="UnobservableInputsAxis" xlink:title="definition: DetailedInformationAboutContingentConsiderationTable to UnobservableInputsAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UnobservableInputsDomain" xlink:label="UnobservableInputsDomain" xlink:title="UnobservableInputsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="UnobservableInputsAxis" xlink:to="UnobservableInputsDomain" xlink:title="definition: UnobservableInputsAxis to UnobservableInputsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UnobservableInputsDomain" xlink:label="UnobservableInputsDomain_2" xlink:title="UnobservableInputsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="UnobservableInputsAxis" xlink:to="UnobservableInputsDomain_2" xlink:title="definition: UnobservableInputsAxis to UnobservableInputsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_RiskAdjustedPostTaxDiscountRateMember" xlink:label="RiskAdjustedPostTaxDiscountRateMember" xlink:title="RiskAdjustedPostTaxDiscountRateMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="UnobservableInputsDomain" xlink:to="RiskAdjustedPostTaxDiscountRateMember" xlink:title="definition: UnobservableInputsDomain to RiskAdjustedPostTaxDiscountRateMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ExpectedSalesVolumeMember" xlink:label="ExpectedSalesVolumeMember" xlink:title="ExpectedSalesVolumeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="UnobservableInputsDomain" xlink:to="ExpectedSalesVolumeMember" xlink:title="definition: UnobservableInputsDomain to ExpectedSalesVolumeMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_NetSalesPricePerUnitMember" xlink:label="NetSalesPricePerUnitMember" xlink:title="NetSalesPricePerUnitMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="UnobservableInputsDomain" xlink:to="NetSalesPricePerUnitMember" xlink:title="definition: UnobservableInputsDomain to NetSalesPricePerUnitMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ApprovalForMarketingAuthorizationProbabilitySuccessFactorMember" xlink:label="ApprovalForMarketingAuthorizationProbabilitySuccessFactorMember" xlink:title="ApprovalForMarketingAuthorizationProbabilitySuccessFactorMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="UnobservableInputsDomain" xlink:to="ApprovalForMarketingAuthorizationProbabilitySuccessFactorMember" xlink:title="definition: UnobservableInputsDomain to ApprovalForMarketingAuthorizationProbabilitySuccessFactorMember" order="4.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ContingentConsiderationIsoTherapeuticsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfBusinessCombinationsLineItems" xlink:label="DisclosureOfBusinessCombinationsLineItems" xlink:title="DisclosureOfBusinessCombinationsLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" xlink:label="AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" xlink:title="AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesIncurred" xlink:label="LiabilitiesIncurred" xlink:title="LiabilitiesIncurred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="LiabilitiesIncurred" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to LiabilitiesIncurred" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfBusinessCombinationsTable" xlink:label="DisclosureOfBusinessCombinationsTable" xlink:title="DisclosureOfBusinessCombinationsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="DisclosureOfBusinessCombinationsTable" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to DisclosureOfBusinessCombinationsTable" order="3.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsAxis" xlink:label="BusinessCombinationsAxis" xlink:title="BusinessCombinationsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfBusinessCombinationsTable" xlink:to="BusinessCombinationsAxis" xlink:title="definition: DisclosureOfBusinessCombinationsTable to BusinessCombinationsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain_2" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain_2" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsMember" xlink:label="BusinessCombinationsMember" xlink:title="BusinessCombinationsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="BusinessCombinationsMember" xlink:title="definition: BusinessCombinationsDomain to BusinessCombinationsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IsoTherapeuticsGroupLLCMember" xlink:label="IsoTherapeuticsGroupLLCMember" xlink:title="IsoTherapeuticsGroupLLCMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsMember" xlink:to="IsoTherapeuticsGroupLLCMember" xlink:title="definition: BusinessCombinationsMember to IsoTherapeuticsGroupLLCMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ContingentConsiderationArtmsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfBusinessCombinationsLineItems" xlink:label="DisclosureOfBusinessCombinationsLineItems" xlink:title="DisclosureOfBusinessCombinationsLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_FuturePaymentContingentOnMilestoneAbstract" xlink:label="FuturePaymentContingentOnMilestoneAbstract" xlink:title="FuturePaymentContingentOnMilestoneAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="FuturePaymentContingentOnMilestoneAbstract" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to FuturePaymentContingentOnMilestoneAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ContingentConsiderationValuationAbstract" xlink:label="ContingentConsiderationValuationAbstract" xlink:title="ContingentConsiderationValuationAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="ContingentConsiderationValuationAbstract" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to ContingentConsiderationValuationAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AmountOfIncreaseDecreaseInPostTaxDiscountRateWouldDecreaseIncreaseContingentConsideration" xlink:label="AmountOfIncreaseDecreaseInPostTaxDiscountRateWouldDecreaseIncreaseContingentConsideration" xlink:title="AmountOfIncreaseDecreaseInPostTaxDiscountRateWouldDecreaseIncreaseContingentConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AmountOfIncreaseDecreaseInPostTaxDiscountRateWouldDecreaseIncreaseContingentConsideration" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AmountOfIncreaseDecreaseInPostTaxDiscountRateWouldDecreaseIncreaseContingentConsideration" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AmountOfIncreaseDecreaseInSalesVolumesWouldIncreaseDecreaseContingentConsideration" xlink:label="AmountOfIncreaseDecreaseInSalesVolumesWouldIncreaseDecreaseContingentConsideration" xlink:title="AmountOfIncreaseDecreaseInSalesVolumesWouldIncreaseDecreaseContingentConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AmountOfIncreaseDecreaseInSalesVolumesWouldIncreaseDecreaseContingentConsideration" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AmountOfIncreaseDecreaseInSalesVolumesWouldIncreaseDecreaseContingentConsideration" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AmountOfIncreaseDecreaseInNetSalesPricePerUnitWouldIncreaseDecreaseContingentConsideration" xlink:label="AmountOfIncreaseDecreaseInNetSalesPricePerUnitWouldIncreaseDecreaseContingentConsideration" xlink:title="AmountOfIncreaseDecreaseInNetSalesPricePerUnitWouldIncreaseDecreaseContingentConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AmountOfIncreaseDecreaseInNetSalesPricePerUnitWouldIncreaseDecreaseContingentConsideration" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AmountOfIncreaseDecreaseInNetSalesPricePerUnitWouldIncreaseDecreaseContingentConsideration" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AmountOfIncreaseDecreaseInProbabilityOfSuccessFactorWouldIncreaseDecreaseContingentConsideration" xlink:label="AmountOfIncreaseDecreaseInProbabilityOfSuccessFactorWouldIncreaseDecreaseContingentConsideration" xlink:title="AmountOfIncreaseDecreaseInProbabilityOfSuccessFactorWouldIncreaseDecreaseContingentConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="AmountOfIncreaseDecreaseInProbabilityOfSuccessFactorWouldIncreaseDecreaseContingentConsideration" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to AmountOfIncreaseDecreaseInProbabilityOfSuccessFactorWouldIncreaseDecreaseContingentConsideration" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ContingentConsiderationRecognisedAsOfAcquisitionDate" xlink:label="ContingentConsiderationRecognisedAsOfAcquisitionDate" xlink:title="ContingentConsiderationRecognisedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="ContingentConsiderationRecognisedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to ContingentConsiderationRecognisedAsOfAcquisitionDate" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DateOfTerminationOfEarnOuts" xlink:label="DateOfTerminationOfEarnOuts" xlink:title="DateOfTerminationOfEarnOuts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="DateOfTerminationOfEarnOuts" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to DateOfTerminationOfEarnOuts" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PercentageOfPostTaxDiscountRateContingentConsideration" xlink:label="PercentageOfPostTaxDiscountRateContingentConsideration" xlink:title="PercentageOfPostTaxDiscountRateContingentConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="PercentageOfPostTaxDiscountRateContingentConsideration" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to PercentageOfPostTaxDiscountRateContingentConsideration" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfBusinessCombinationsTable" xlink:label="DisclosureOfBusinessCombinationsTable" xlink:title="DisclosureOfBusinessCombinationsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfBusinessCombinationsLineItems" xlink:to="DisclosureOfBusinessCombinationsTable" xlink:title="definition: DisclosureOfBusinessCombinationsLineItems to DisclosureOfBusinessCombinationsTable" order="10.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UnobservableInputsAxis" xlink:label="UnobservableInputsAxis" xlink:title="UnobservableInputsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfBusinessCombinationsTable" xlink:to="UnobservableInputsAxis" xlink:title="definition: DisclosureOfBusinessCombinationsTable to UnobservableInputsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UnobservableInputsDomain" xlink:label="UnobservableInputsDomain" xlink:title="UnobservableInputsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="UnobservableInputsAxis" xlink:to="UnobservableInputsDomain" xlink:title="definition: UnobservableInputsAxis to UnobservableInputsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_UnobservableInputsDomain" xlink:label="UnobservableInputsDomain_2" xlink:title="UnobservableInputsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="UnobservableInputsAxis" xlink:to="UnobservableInputsDomain_2" xlink:title="definition: UnobservableInputsAxis to UnobservableInputsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_RiskAdjustedPostTaxDiscountRateMember" xlink:label="RiskAdjustedPostTaxDiscountRateMember" xlink:title="RiskAdjustedPostTaxDiscountRateMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="UnobservableInputsDomain" xlink:to="RiskAdjustedPostTaxDiscountRateMember" xlink:title="definition: UnobservableInputsDomain to RiskAdjustedPostTaxDiscountRateMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ExpectedSalesVolumesARTMSAndTelixProductsMember" xlink:label="ExpectedSalesVolumesARTMSAndTelixProductsMember" xlink:title="ExpectedSalesVolumesARTMSAndTelixProductsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="UnobservableInputsDomain" xlink:to="ExpectedSalesVolumesARTMSAndTelixProductsMember" xlink:title="definition: UnobservableInputsDomain to ExpectedSalesVolumesARTMSAndTelixProductsMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_NetSalesPricePerUnitMember" xlink:label="NetSalesPricePerUnitMember" xlink:title="NetSalesPricePerUnitMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="UnobservableInputsDomain" xlink:to="NetSalesPricePerUnitMember" xlink:title="definition: UnobservableInputsDomain to NetSalesPricePerUnitMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_MilestoneAchievementProbabilityOfSuccessFactorMember" xlink:label="MilestoneAchievementProbabilityOfSuccessFactorMember" xlink:title="MilestoneAchievementProbabilityOfSuccessFactorMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="UnobservableInputsDomain" xlink:to="MilestoneAchievementProbabilityOfSuccessFactorMember" xlink:title="definition: UnobservableInputsDomain to MilestoneAchievementProbabilityOfSuccessFactorMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfBusinessCombinationsTable" xlink:to="RangeAxis" xlink:title="definition: DisclosureOfBusinessCombinationsTable to RangeAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="RangeDomain" xlink:title="RangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeDomain" xlink:title="definition: RangeAxis to RangeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="RangeDomain_2" xlink:title="RangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeDomain_2" xlink:title="definition: RangeAxis to RangeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BottomOfRangeMember" xlink:label="BottomOfRangeMember" xlink:title="BottomOfRangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeDomain" xlink:to="BottomOfRangeMember" xlink:title="definition: RangeDomain to BottomOfRangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TopOfRangeMember" xlink:label="TopOfRangeMember" xlink:title="TopOfRangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeDomain" xlink:to="TopOfRangeMember" xlink:title="definition: RangeDomain to TopOfRangeMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EmployeeBenefitObligationsDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EmployeeBenefitObligationsDetailsCalc2" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EquityShareCapitalDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfClassesOfShareCapitalLineItems" xlink:label="DisclosureOfClassesOfShareCapitalLineItems" xlink:title="DisclosureOfClassesOfShareCapitalLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfClassesOfShareCapitalAbstract" xlink:label="DisclosureOfClassesOfShareCapitalAbstract" xlink:title="DisclosureOfClassesOfShareCapitalAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="DisclosureOfClassesOfShareCapitalAbstract" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to DisclosureOfClassesOfShareCapitalAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfSharesOutstanding" xlink:label="NumberOfSharesOutstanding" xlink:title="NumberOfSharesOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="NumberOfSharesOutstanding" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to NumberOfSharesOutstanding" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IssuedCapital" xlink:label="IssuedCapital" xlink:title="IssuedCapital" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="IssuedCapital" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to IssuedCapital" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseSharesIssuedThroughExerciseOfShareOptionsAndWarrants" xlink:label="IncreaseDecreaseSharesIssuedThroughExerciseOfShareOptionsAndWarrants" xlink:title="IncreaseDecreaseSharesIssuedThroughExerciseOfShareOptionsAndWarrants" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="IncreaseDecreaseSharesIssuedThroughExerciseOfShareOptionsAndWarrants" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to IncreaseDecreaseSharesIssuedThroughExerciseOfShareOptionsAndWarrants" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_SharesIssuedThroughExerciseOfShareOptionsAndWarrants" xlink:label="SharesIssuedThroughExerciseOfShareOptionsAndWarrants" xlink:title="SharesIssuedThroughExerciseOfShareOptionsAndWarrants" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="SharesIssuedThroughExerciseOfShareOptionsAndWarrants" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to SharesIssuedThroughExerciseOfShareOptionsAndWarrants" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseThroughContributionsOfEquityShares" xlink:label="IncreaseDecreaseThroughContributionsOfEquityShares" xlink:title="IncreaseDecreaseThroughContributionsOfEquityShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="IncreaseDecreaseThroughContributionsOfEquityShares" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to IncreaseDecreaseThroughContributionsOfEquityShares" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseThroughContributionsOfEquity" xlink:label="IncreaseDecreaseThroughContributionsOfEquity" xlink:title="IncreaseDecreaseThroughContributionsOfEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="IncreaseDecreaseThroughContributionsOfEquity" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to IncreaseDecreaseThroughContributionsOfEquity" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseInNumberOfSharesIssued" xlink:label="IncreaseDecreaseInNumberOfSharesIssued" xlink:title="IncreaseDecreaseInNumberOfSharesIssued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="IncreaseDecreaseInNumberOfSharesIssued" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to IncreaseDecreaseInNumberOfSharesIssued" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IssueOfEquity" xlink:label="IssueOfEquity" xlink:title="IssueOfEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="IssueOfEquity" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to IssueOfEquity" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseInTransactionCostsArisingOnNewShareIssued" xlink:label="IncreaseDecreaseInTransactionCostsArisingOnNewShareIssued" xlink:title="IncreaseDecreaseInTransactionCostsArisingOnNewShareIssued" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="IncreaseDecreaseInTransactionCostsArisingOnNewShareIssued" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to IncreaseDecreaseInTransactionCostsArisingOnNewShareIssued" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseInTransactionCostsArisingOnNewShareIssues" xlink:label="IncreaseDecreaseInTransactionCostsArisingOnNewShareIssues" xlink:title="IncreaseDecreaseInTransactionCostsArisingOnNewShareIssues" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="IncreaseDecreaseInTransactionCostsArisingOnNewShareIssues" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to IncreaseDecreaseInTransactionCostsArisingOnNewShareIssues" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ParValuePerShare" xlink:label="ParValuePerShare" xlink:title="ParValuePerShare" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="ParValuePerShare" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to ParValuePerShare" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PaymentsForInstitutionalPlacementCost" xlink:label="PaymentsForInstitutionalPlacementCost" xlink:title="PaymentsForInstitutionalPlacementCost" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="PaymentsForInstitutionalPlacementCost" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to PaymentsForInstitutionalPlacementCost" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PaymentsForShareIssueCosts" xlink:label="PaymentsForShareIssueCosts" xlink:title="PaymentsForShareIssueCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="PaymentsForShareIssueCosts" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to PaymentsForShareIssueCosts" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_VolumeWeightedAveragePeriod" xlink:label="VolumeWeightedAveragePeriod" xlink:title="VolumeWeightedAveragePeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="VolumeWeightedAveragePeriod" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to VolumeWeightedAveragePeriod" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_VolumeWeightedAveragePriceOfEquityInstruments" xlink:label="VolumeWeightedAveragePriceOfEquityInstruments" xlink:title="VolumeWeightedAveragePriceOfEquityInstruments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="VolumeWeightedAveragePriceOfEquityInstruments" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to VolumeWeightedAveragePriceOfEquityInstruments" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfSharesIssuedAndFullyPaid" xlink:label="NumberOfSharesIssuedAndFullyPaid" xlink:title="NumberOfSharesIssuedAndFullyPaid" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="NumberOfSharesIssuedAndFullyPaid" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to NumberOfSharesIssuedAndFullyPaid" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_WeightedAverageShares" xlink:label="WeightedAverageShares" xlink:title="WeightedAverageShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="WeightedAverageShares" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to WeightedAverageShares" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfClassesOfShareCapitalTable" xlink:label="DisclosureOfClassesOfShareCapitalTable" xlink:title="DisclosureOfClassesOfShareCapitalTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="DisclosureOfClassesOfShareCapitalTable" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to DisclosureOfClassesOfShareCapitalTable" order="19.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfShareCapitalAxis" xlink:label="ClassesOfShareCapitalAxis" xlink:title="ClassesOfShareCapitalAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfClassesOfShareCapitalTable" xlink:to="ClassesOfShareCapitalAxis" xlink:title="definition: DisclosureOfClassesOfShareCapitalTable to ClassesOfShareCapitalAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfShareCapitalDomain" xlink:label="ClassesOfShareCapitalDomain" xlink:title="ClassesOfShareCapitalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ClassesOfShareCapitalAxis" xlink:to="ClassesOfShareCapitalDomain" xlink:title="definition: ClassesOfShareCapitalAxis to ClassesOfShareCapitalDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfShareCapitalDomain" xlink:label="ClassesOfShareCapitalDomain_2" xlink:title="ClassesOfShareCapitalDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassesOfShareCapitalAxis" xlink:to="ClassesOfShareCapitalDomain_2" xlink:title="definition: ClassesOfShareCapitalAxis to ClassesOfShareCapitalDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OrdinarySharesMember" xlink:label="OrdinarySharesMember" xlink:title="OrdinarySharesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfShareCapitalDomain" xlink:to="OrdinarySharesMember" xlink:title="definition: ClassesOfShareCapitalDomain to OrdinarySharesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityAxis" xlink:label="ComponentsOfEquityAxis" xlink:title="ComponentsOfEquityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfClassesOfShareCapitalTable" xlink:to="ComponentsOfEquityAxis" xlink:title="definition: DisclosureOfClassesOfShareCapitalTable to ComponentsOfEquityAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ComponentsOfEquityDomain" xlink:title="ComponentsOfEquityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ComponentsOfEquityAxis" xlink:to="ComponentsOfEquityDomain" xlink:title="definition: ComponentsOfEquityAxis to ComponentsOfEquityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ComponentsOfEquityDomain_2" xlink:title="ComponentsOfEquityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ComponentsOfEquityAxis" xlink:to="ComponentsOfEquityDomain_2" xlink:title="definition: ComponentsOfEquityAxis to ComponentsOfEquityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IssuedCapitalMember" xlink:label="IssuedCapitalMember" xlink:title="IssuedCapitalMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComponentsOfEquityDomain" xlink:to="IssuedCapitalMember" xlink:title="definition: ComponentsOfEquityDomain to IssuedCapitalMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsAxis" xlink:label="BusinessCombinationsAxis" xlink:title="BusinessCombinationsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfClassesOfShareCapitalTable" xlink:to="BusinessCombinationsAxis" xlink:title="definition: DisclosureOfClassesOfShareCapitalTable to BusinessCombinationsAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain_2" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain_2" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DedicaidGmbHMember" xlink:label="DedicaidGmbHMember" xlink:title="DedicaidGmbHMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="DedicaidGmbHMember" xlink:title="definition: BusinessCombinationsDomain to DedicaidGmbHMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_LightpointMedicalMember" xlink:label="LightpointMedicalMember" xlink:title="LightpointMedicalMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="LightpointMedicalMember" xlink:title="definition: BusinessCombinationsDomain to LightpointMedicalMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IsoTherapeuticsGroupLLCMember" xlink:label="IsoTherapeuticsGroupLLCMember" xlink:title="IsoTherapeuticsGroupLLCMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="IsoTherapeuticsGroupLLCMember" xlink:title="definition: BusinessCombinationsDomain to IsoTherapeuticsGroupLLCMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ARTMSIncMember" xlink:label="ARTMSIncMember" xlink:title="ARTMSIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="ARTMSIncMember" xlink:title="definition: BusinessCombinationsDomain to ARTMSIncMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_QSAMBiosciencesIncMember" xlink:label="QSAMBiosciencesIncMember" xlink:title="QSAMBiosciencesIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="QSAMBiosciencesIncMember" xlink:title="definition: BusinessCombinationsDomain to QSAMBiosciencesIncMember" order="5.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EquityShareCapitalReserveDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfClassesOfShareCapitalLineItems" xlink:label="DisclosureOfClassesOfShareCapitalLineItems" xlink:title="DisclosureOfClassesOfShareCapitalLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ShareCapitalReserveAbstract" xlink:label="ShareCapitalReserveAbstract" xlink:title="ShareCapitalReserveAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="ShareCapitalReserveAbstract" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to ShareCapitalReserveAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfSharesOutstanding" xlink:label="NumberOfSharesOutstanding" xlink:title="NumberOfSharesOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="NumberOfSharesOutstanding" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to NumberOfSharesOutstanding" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_CapitalReserveDeficit" xlink:label="CapitalReserveDeficit" xlink:title="CapitalReserveDeficit" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="CapitalReserveDeficit" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to CapitalReserveDeficit" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseThroughTreasurySharesAcquired" xlink:label="IncreaseDecreaseThroughTreasurySharesAcquired" xlink:title="IncreaseDecreaseThroughTreasurySharesAcquired" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="IncreaseDecreaseThroughTreasurySharesAcquired" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to IncreaseDecreaseThroughTreasurySharesAcquired" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PurchaseOfTreasuryShares" xlink:label="PurchaseOfTreasuryShares" xlink:title="PurchaseOfTreasuryShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="PurchaseOfTreasuryShares" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to PurchaseOfTreasuryShares" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseThroughIssueOfConvertibleBonds" xlink:label="IncreaseDecreaseThroughIssueOfConvertibleBonds" xlink:title="IncreaseDecreaseThroughIssueOfConvertibleBonds" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="IncreaseDecreaseThroughIssueOfConvertibleBonds" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to IncreaseDecreaseThroughIssueOfConvertibleBonds" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IssueOfConvertibleInstruments" xlink:label="IssueOfConvertibleInstruments" xlink:title="IssueOfConvertibleInstruments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="IssueOfConvertibleInstruments" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to IssueOfConvertibleInstruments" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseThroughTransactionCostsArisingOnConvertibleBondsIssueShares" xlink:label="IncreaseDecreaseThroughTransactionCostsArisingOnConvertibleBondsIssueShares" xlink:title="IncreaseDecreaseThroughTransactionCostsArisingOnConvertibleBondsIssueShares" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="IncreaseDecreaseThroughTransactionCostsArisingOnConvertibleBondsIssueShares" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to IncreaseDecreaseThroughTransactionCostsArisingOnConvertibleBondsIssueShares" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseThroughTransactionCostsArisingOnConvertibleBondsIssue" xlink:label="IncreaseDecreaseThroughTransactionCostsArisingOnConvertibleBondsIssue" xlink:title="IncreaseDecreaseThroughTransactionCostsArisingOnConvertibleBondsIssue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="IncreaseDecreaseThroughTransactionCostsArisingOnConvertibleBondsIssue" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to IncreaseDecreaseThroughTransactionCostsArisingOnConvertibleBondsIssue" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseThroughSharesAllocatedToEmployees" xlink:label="IncreaseDecreaseThroughSharesAllocatedToEmployees" xlink:title="IncreaseDecreaseThroughSharesAllocatedToEmployees" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="IncreaseDecreaseThroughSharesAllocatedToEmployees" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to IncreaseDecreaseThroughSharesAllocatedToEmployees" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_SharesAllocatedToEmployeesValue" xlink:label="SharesAllocatedToEmployeesValue" xlink:title="SharesAllocatedToEmployeesValue" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="SharesAllocatedToEmployeesValue" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to SharesAllocatedToEmployeesValue" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfClassesOfShareCapitalTable" xlink:label="DisclosureOfClassesOfShareCapitalTable" xlink:title="DisclosureOfClassesOfShareCapitalTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="DisclosureOfClassesOfShareCapitalTable" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to DisclosureOfClassesOfShareCapitalTable" order="12.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityAxis" xlink:label="ComponentsOfEquityAxis" xlink:title="ComponentsOfEquityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfClassesOfShareCapitalTable" xlink:to="ComponentsOfEquityAxis" xlink:title="definition: DisclosureOfClassesOfShareCapitalTable to ComponentsOfEquityAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ComponentsOfEquityDomain" xlink:title="ComponentsOfEquityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ComponentsOfEquityAxis" xlink:to="ComponentsOfEquityDomain" xlink:title="definition: ComponentsOfEquityAxis to ComponentsOfEquityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ComponentsOfEquityDomain_2" xlink:title="ComponentsOfEquityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ComponentsOfEquityAxis" xlink:to="ComponentsOfEquityDomain_2" xlink:title="definition: ComponentsOfEquityAxis to ComponentsOfEquityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CapitalReserveMember" xlink:label="CapitalReserveMember" xlink:title="CapitalReserveMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComponentsOfEquityDomain" xlink:to="CapitalReserveMember" xlink:title="definition: ComponentsOfEquityDomain to CapitalReserveMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EquityOtherReservesDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfClassesOfShareCapitalLineItems" xlink:label="DisclosureOfClassesOfShareCapitalLineItems" xlink:title="DisclosureOfClassesOfShareCapitalLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_OtherReservesAbstract" xlink:label="OtherReservesAbstract" xlink:title="OtherReservesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="OtherReservesAbstract" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to OtherReservesAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Equity" xlink:label="Equity" xlink:title="Equity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="Equity" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to Equity" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherComprehensiveIncome" xlink:label="OtherComprehensiveIncome" xlink:title="OtherComprehensiveIncome" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="OtherComprehensiveIncome" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to OtherComprehensiveIncome" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComprehensiveIncome" xlink:label="ComprehensiveIncome" xlink:title="ComprehensiveIncome" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="ComprehensiveIncome" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to ComprehensiveIncome" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseThroughSharebasedPaymentTransactions" xlink:label="IncreaseDecreaseThroughSharebasedPaymentTransactions" xlink:title="IncreaseDecreaseThroughSharebasedPaymentTransactions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="IncreaseDecreaseThroughSharebasedPaymentTransactions" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to IncreaseDecreaseThroughSharebasedPaymentTransactions" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseThroughShareBasedPaymentTransactionsAssociatedWithAcquisitionsEquity" xlink:label="IncreaseDecreaseThroughShareBasedPaymentTransactionsAssociatedWithAcquisitionsEquity" xlink:title="IncreaseDecreaseThroughShareBasedPaymentTransactionsAssociatedWithAcquisitionsEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="IncreaseDecreaseThroughShareBasedPaymentTransactionsAssociatedWithAcquisitionsEquity" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to IncreaseDecreaseThroughShareBasedPaymentTransactionsAssociatedWithAcquisitionsEquity" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IncreaseDecreaseThroughTransferOnExerciseOfOptionsEquity" xlink:label="IncreaseDecreaseThroughTransferOnExerciseOfOptionsEquity" xlink:title="IncreaseDecreaseThroughTransferOnExerciseOfOptionsEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="IncreaseDecreaseThroughTransferOnExerciseOfOptionsEquity" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to IncreaseDecreaseThroughTransferOnExerciseOfOptionsEquity" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ChangesInEquity" xlink:label="ChangesInEquity" xlink:title="ChangesInEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="ChangesInEquity" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to ChangesInEquity" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfClassesOfShareCapitalTable" xlink:label="DisclosureOfClassesOfShareCapitalTable" xlink:title="DisclosureOfClassesOfShareCapitalTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="DisclosureOfClassesOfShareCapitalTable" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to DisclosureOfClassesOfShareCapitalTable" order="9.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityAxis" xlink:label="ComponentsOfEquityAxis" xlink:title="ComponentsOfEquityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfClassesOfShareCapitalTable" xlink:to="ComponentsOfEquityAxis" xlink:title="definition: DisclosureOfClassesOfShareCapitalTable to ComponentsOfEquityAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ComponentsOfEquityDomain" xlink:title="ComponentsOfEquityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ComponentsOfEquityAxis" xlink:to="ComponentsOfEquityDomain" xlink:title="definition: ComponentsOfEquityAxis to ComponentsOfEquityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ComponentsOfEquityDomain_2" xlink:title="ComponentsOfEquityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ComponentsOfEquityAxis" xlink:to="ComponentsOfEquityDomain_2" xlink:title="definition: ComponentsOfEquityAxis to ComponentsOfEquityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ReserveOfExchangeDifferencesOnTranslationMember" xlink:label="ReserveOfExchangeDifferencesOnTranslationMember" xlink:title="ReserveOfExchangeDifferencesOnTranslationMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComponentsOfEquityDomain" xlink:to="ReserveOfExchangeDifferencesOnTranslationMember" xlink:title="definition: ComponentsOfEquityDomain to ReserveOfExchangeDifferencesOnTranslationMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ReserveOfSharebasedPaymentsMember" xlink:label="ReserveOfSharebasedPaymentsMember" xlink:title="ReserveOfSharebasedPaymentsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComponentsOfEquityDomain" xlink:to="ReserveOfSharebasedPaymentsMember" xlink:title="definition: ComponentsOfEquityDomain to ReserveOfSharebasedPaymentsMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncomeMember" xlink:label="ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncomeMember" xlink:title="ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncomeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComponentsOfEquityDomain" xlink:to="ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncomeMember" xlink:title="definition: ComponentsOfEquityDomain to ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncomeMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherReservesMember" xlink:label="OtherReservesMember" xlink:title="OtherReservesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComponentsOfEquityDomain" xlink:to="OtherReservesMember" xlink:title="definition: ComponentsOfEquityDomain to OtherReservesMember" order="4.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EquitySharebasedPaymentsReserveDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfClassesOfShareCapitalLineItems" xlink:label="DisclosureOfClassesOfShareCapitalLineItems" xlink:title="DisclosureOfClassesOfShareCapitalLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ShareBasedPaymentsReserveAbstract" xlink:label="ShareBasedPaymentsReserveAbstract" xlink:title="ShareBasedPaymentsReserveAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="ShareBasedPaymentsReserveAbstract" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to ShareBasedPaymentsReserveAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfSharesOutstanding" xlink:label="NumberOfSharesOutstanding" xlink:title="NumberOfSharesOutstanding" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="NumberOfSharesOutstanding" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to NumberOfSharesOutstanding" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfShareOptionsGrantedInSharebasedPaymentArrangement" xlink:label="NumberOfShareOptionsGrantedInSharebasedPaymentArrangement" xlink:title="NumberOfShareOptionsGrantedInSharebasedPaymentArrangement" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="NumberOfShareOptionsGrantedInSharebasedPaymentArrangement" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to NumberOfShareOptionsGrantedInSharebasedPaymentArrangement" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_NumberOfPerformanceRightGrantedInShareBasedPaymentArrangement" xlink:label="NumberOfPerformanceRightGrantedInShareBasedPaymentArrangement" xlink:title="NumberOfPerformanceRightGrantedInShareBasedPaymentArrangement" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="NumberOfPerformanceRightGrantedInShareBasedPaymentArrangement" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to NumberOfPerformanceRightGrantedInShareBasedPaymentArrangement" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfShareOptionsExercisedInSharebasedPaymentArrangement" xlink:label="NumberOfShareOptionsExercisedInSharebasedPaymentArrangement" xlink:title="NumberOfShareOptionsExercisedInSharebasedPaymentArrangement" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="NumberOfShareOptionsExercisedInSharebasedPaymentArrangement" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to NumberOfShareOptionsExercisedInSharebasedPaymentArrangement" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfShareOptionsForfeitedInSharebasedPaymentArrangement" xlink:label="NumberOfShareOptionsForfeitedInSharebasedPaymentArrangement" xlink:title="NumberOfShareOptionsForfeitedInSharebasedPaymentArrangement" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="NumberOfShareOptionsForfeitedInSharebasedPaymentArrangement" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to NumberOfShareOptionsForfeitedInSharebasedPaymentArrangement" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfClassesOfShareCapitalTable" xlink:label="DisclosureOfClassesOfShareCapitalTable" xlink:title="DisclosureOfClassesOfShareCapitalTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="DisclosureOfClassesOfShareCapitalTable" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to DisclosureOfClassesOfShareCapitalTable" order="7.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityAxis" xlink:label="ComponentsOfEquityAxis" xlink:title="ComponentsOfEquityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfClassesOfShareCapitalTable" xlink:to="ComponentsOfEquityAxis" xlink:title="definition: DisclosureOfClassesOfShareCapitalTable to ComponentsOfEquityAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ComponentsOfEquityDomain" xlink:title="ComponentsOfEquityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ComponentsOfEquityAxis" xlink:to="ComponentsOfEquityDomain" xlink:title="definition: ComponentsOfEquityAxis to ComponentsOfEquityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ComponentsOfEquityDomain_2" xlink:title="ComponentsOfEquityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ComponentsOfEquityAxis" xlink:to="ComponentsOfEquityDomain_2" xlink:title="definition: ComponentsOfEquityAxis to ComponentsOfEquityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ReserveOfSharebasedPaymentsMember" xlink:label="ReserveOfSharebasedPaymentsMember" xlink:title="ReserveOfSharebasedPaymentsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComponentsOfEquityDomain" xlink:to="ReserveOfSharebasedPaymentsMember" xlink:title="definition: ComponentsOfEquityDomain to ReserveOfSharebasedPaymentsMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EquityFinancialAssetsAtFvociReserveDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfClassesOfShareCapitalLineItems" xlink:label="DisclosureOfClassesOfShareCapitalLineItems" xlink:title="DisclosureOfClassesOfShareCapitalLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_FinancialAssetsAtFVOCIReserveAbstract" xlink:label="FinancialAssetsAtFVOCIReserveAbstract" xlink:title="FinancialAssetsAtFVOCIReserveAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="FinancialAssetsAtFVOCIReserveAbstract" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to FinancialAssetsAtFVOCIReserveAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncome" xlink:label="ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncome" xlink:title="ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncome" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncome" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncome" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_OtherComprehensiveIncome" xlink:label="OtherComprehensiveIncome" xlink:title="OtherComprehensiveIncome" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="OtherComprehensiveIncome" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to OtherComprehensiveIncome" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DeferredTaxExpenseIncome" xlink:label="DeferredTaxExpenseIncome" xlink:title="DeferredTaxExpenseIncome" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="DeferredTaxExpenseIncome" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to DeferredTaxExpenseIncome" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfClassesOfShareCapitalTable" xlink:label="DisclosureOfClassesOfShareCapitalTable" xlink:title="DisclosureOfClassesOfShareCapitalTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfClassesOfShareCapitalLineItems" xlink:to="DisclosureOfClassesOfShareCapitalTable" xlink:title="definition: DisclosureOfClassesOfShareCapitalLineItems to DisclosureOfClassesOfShareCapitalTable" order="5.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityAxis" xlink:label="ComponentsOfEquityAxis" xlink:title="ComponentsOfEquityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfClassesOfShareCapitalTable" xlink:to="ComponentsOfEquityAxis" xlink:title="definition: DisclosureOfClassesOfShareCapitalTable to ComponentsOfEquityAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ComponentsOfEquityDomain" xlink:title="ComponentsOfEquityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ComponentsOfEquityAxis" xlink:to="ComponentsOfEquityDomain" xlink:title="definition: ComponentsOfEquityAxis to ComponentsOfEquityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ComponentsOfEquityDomain" xlink:label="ComponentsOfEquityDomain_2" xlink:title="ComponentsOfEquityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ComponentsOfEquityAxis" xlink:to="ComponentsOfEquityDomain_2" xlink:title="definition: ComponentsOfEquityAxis to ComponentsOfEquityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncomeMember" xlink:label="ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncomeMember" xlink:title="ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncomeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ComponentsOfEquityDomain" xlink:to="ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncomeMember" xlink:title="definition: ComponentsOfEquityDomain to ReserveOfFinancialAssetsAtFairValueThroughOtherComprehensiveIncomeMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/SharebasedPaymentsEquityIncentivePlanAndOptionsDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/SharebasedPaymentsNumberAndWeightedAverageExercisePriceOfStockOptionsDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/SharebasedPaymentsShareBasedCompensationExpenseDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/SharebasedPaymentsNumberOfOptionsIssuedUnderEquityIncentivePlanOutstandingDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:label="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:title="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_NumberOfOptionsIssuedUnderEquityIncentivePlanAbstract" xlink:label="NumberOfOptionsIssuedUnderEquityIncentivePlanAbstract" xlink:title="NumberOfOptionsIssuedUnderEquityIncentivePlanAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="NumberOfOptionsIssuedUnderEquityIncentivePlanAbstract" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to NumberOfOptionsIssuedUnderEquityIncentivePlanAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DateOfGrantOfSharebasedPaymentArrangement" xlink:label="DateOfGrantOfSharebasedPaymentArrangement" xlink:title="DateOfGrantOfSharebasedPaymentArrangement" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="DateOfGrantOfSharebasedPaymentArrangement" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to DateOfGrantOfSharebasedPaymentArrangement" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DateOfVestingShareBasedPaymentArrangement" xlink:label="DateOfVestingShareBasedPaymentArrangement" xlink:title="DateOfVestingShareBasedPaymentArrangement" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="DateOfVestingShareBasedPaymentArrangement" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to DateOfVestingShareBasedPaymentArrangement" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DateOfExpiryShareBasedPaymentArrangement" xlink:label="DateOfExpiryShareBasedPaymentArrangement" xlink:title="DateOfExpiryShareBasedPaymentArrangement" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="DateOfExpiryShareBasedPaymentArrangement" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to DateOfExpiryShareBasedPaymentArrangement" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_WeightedAverageExercisePriceOfShareOptionsExercisedInSharebasedPaymentArrangement2019" xlink:label="WeightedAverageExercisePriceOfShareOptionsExercisedInSharebasedPaymentArrangement2019" xlink:title="WeightedAverageExercisePriceOfShareOptionsExercisedInSharebasedPaymentArrangement2019" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="WeightedAverageExercisePriceOfShareOptionsExercisedInSharebasedPaymentArrangement2019" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to WeightedAverageExercisePriceOfShareOptionsExercisedInSharebasedPaymentArrangement2019" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfOutstandingShareOptions" xlink:label="NumberOfOutstandingShareOptions" xlink:title="NumberOfOutstandingShareOptions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="NumberOfOutstandingShareOptions" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to NumberOfOutstandingShareOptions" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfShareOptionsGrantedInSharebasedPaymentArrangement" xlink:label="NumberOfShareOptionsGrantedInSharebasedPaymentArrangement" xlink:title="NumberOfShareOptionsGrantedInSharebasedPaymentArrangement" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="NumberOfShareOptionsGrantedInSharebasedPaymentArrangement" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to NumberOfShareOptionsGrantedInSharebasedPaymentArrangement" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_NumberOfShareOptionsVestedInShareBasedPaymentArrangement" xlink:label="NumberOfShareOptionsVestedInShareBasedPaymentArrangement" xlink:title="NumberOfShareOptionsVestedInShareBasedPaymentArrangement" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="NumberOfShareOptionsVestedInShareBasedPaymentArrangement" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to NumberOfShareOptionsVestedInShareBasedPaymentArrangement" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfShareOptionsExercisedInSharebasedPaymentArrangement" xlink:label="NumberOfShareOptionsExercisedInSharebasedPaymentArrangement" xlink:title="NumberOfShareOptionsExercisedInSharebasedPaymentArrangement" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="NumberOfShareOptionsExercisedInSharebasedPaymentArrangement" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to NumberOfShareOptionsExercisedInSharebasedPaymentArrangement" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NumberOfShareOptionsExpiredInSharebasedPaymentArrangement" xlink:label="NumberOfShareOptionsExpiredInSharebasedPaymentArrangement" xlink:title="NumberOfShareOptionsExpiredInSharebasedPaymentArrangement" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="NumberOfShareOptionsExpiredInSharebasedPaymentArrangement" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to NumberOfShareOptionsExpiredInSharebasedPaymentArrangement" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:label="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:title="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" order="11.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" xlink:label="TypesOfSharebasedPaymentArrangementsAxis" xlink:title="TypesOfSharebasedPaymentArrangementsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:to="TypesOfSharebasedPaymentArrangementsAxis" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable to TypesOfSharebasedPaymentArrangementsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:label="TypesOfSharebasedPaymentArrangementsDomain" xlink:title="TypesOfSharebasedPaymentArrangementsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TypesOfSharebasedPaymentArrangementsAxis" xlink:to="TypesOfSharebasedPaymentArrangementsDomain" xlink:title="definition: TypesOfSharebasedPaymentArrangementsAxis to TypesOfSharebasedPaymentArrangementsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:label="TypesOfSharebasedPaymentArrangementsDomain_2" xlink:title="TypesOfSharebasedPaymentArrangementsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TypesOfSharebasedPaymentArrangementsAxis" xlink:to="TypesOfSharebasedPaymentArrangementsDomain_2" xlink:title="definition: TypesOfSharebasedPaymentArrangementsAxis to TypesOfSharebasedPaymentArrangementsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ShareOptionsMember" xlink:label="ShareOptionsMember" xlink:title="ShareOptionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TypesOfSharebasedPaymentArrangementsDomain" xlink:to="ShareOptionsMember" xlink:title="definition: TypesOfSharebasedPaymentArrangementsDomain to ShareOptionsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CreationDateAxis" xlink:label="CreationDateAxis" xlink:title="CreationDateAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:to="CreationDateAxis" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable to CreationDateAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DefaultFinancialStatementsDateMember" xlink:label="DefaultFinancialStatementsDateMember" xlink:title="DefaultFinancialStatementsDateMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="CreationDateAxis" xlink:to="DefaultFinancialStatementsDateMember" xlink:title="definition: CreationDateAxis to DefaultFinancialStatementsDateMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DefaultFinancialStatementsDateMember" xlink:label="DefaultFinancialStatementsDateMember_2" xlink:title="DefaultFinancialStatementsDateMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="CreationDateAxis" xlink:to="DefaultFinancialStatementsDateMember_2" xlink:title="definition: CreationDateAxis to DefaultFinancialStatementsDateMember_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateFourMember" xlink:label="GrantDateFourMember" xlink:title="GrantDateFourMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateFourMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateFourMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateFiveMember" xlink:label="GrantDateFiveMember" xlink:title="GrantDateFiveMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateFiveMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateFiveMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateSixMember" xlink:label="GrantDateSixMember" xlink:title="GrantDateSixMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateSixMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateSixMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateSevenMember" xlink:label="GrantDateSevenMember" xlink:title="GrantDateSevenMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateSevenMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateSevenMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateEightMember" xlink:label="GrantDateEightMember" xlink:title="GrantDateEightMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateEightMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateEightMember" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateNineMember" xlink:label="GrantDateNineMember" xlink:title="GrantDateNineMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateNineMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateNineMember" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateTenMember" xlink:label="GrantDateTenMember" xlink:title="GrantDateTenMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateTenMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateTenMember" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateElevenMember" xlink:label="GrantDateElevenMember" xlink:title="GrantDateElevenMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateElevenMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateElevenMember" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateTwelveMember" xlink:label="GrantDateTwelveMember" xlink:title="GrantDateTwelveMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateTwelveMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateTwelveMember" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateThirteenMember" xlink:label="GrantDateThirteenMember" xlink:title="GrantDateThirteenMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateThirteenMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateThirteenMember" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateFourteenMember" xlink:label="GrantDateFourteenMember" xlink:title="GrantDateFourteenMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateFourteenMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateFourteenMember" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateFifteenMember" xlink:label="GrantDateFifteenMember" xlink:title="GrantDateFifteenMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateFifteenMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateFifteenMember" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateSixteenMember" xlink:label="GrantDateSixteenMember" xlink:title="GrantDateSixteenMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateSixteenMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateSixteenMember" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateSeventeenMember" xlink:label="GrantDateSeventeenMember" xlink:title="GrantDateSeventeenMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateSeventeenMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateSeventeenMember" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateEighteenMember" xlink:label="GrantDateEighteenMember" xlink:title="GrantDateEighteenMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateEighteenMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateEighteenMember" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateNineteenMember" xlink:label="GrantDateNineteenMember" xlink:title="GrantDateNineteenMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateNineteenMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateNineteenMember" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateTwentyMember" xlink:label="GrantDateTwentyMember" xlink:title="GrantDateTwentyMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateTwentyMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateTwentyMember" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateTwentyOneMember" xlink:label="GrantDateTwentyOneMember" xlink:title="GrantDateTwentyOneMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateTwentyOneMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateTwentyOneMember" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateTwentyTwoMember" xlink:label="GrantDateTwentyTwoMember" xlink:title="GrantDateTwentyTwoMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateTwentyTwoMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateTwentyTwoMember" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateTwentyThreeMember" xlink:label="GrantDateTwentyThreeMember" xlink:title="GrantDateTwentyThreeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateTwentyThreeMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateTwentyThreeMember" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateTwentyFourMember" xlink:label="GrantDateTwentyFourMember" xlink:title="GrantDateTwentyFourMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateTwentyFourMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateTwentyFourMember" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateTwentyFiveMember" xlink:label="GrantDateTwentyFiveMember" xlink:title="GrantDateTwentyFiveMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateTwentyFiveMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateTwentyFiveMember" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateTwentySixMember" xlink:label="GrantDateTwentySixMember" xlink:title="GrantDateTwentySixMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateTwentySixMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateTwentySixMember" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateTwentySevenMember" xlink:label="GrantDateTwentySevenMember" xlink:title="GrantDateTwentySevenMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateTwentySevenMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateTwentySevenMember" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateTwentyEightMember" xlink:label="GrantDateTwentyEightMember" xlink:title="GrantDateTwentyEightMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateTwentyEightMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateTwentyEightMember" order="25.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateTwentyNineMember" xlink:label="GrantDateTwentyNineMember" xlink:title="GrantDateTwentyNineMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateTwentyNineMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateTwentyNineMember" order="26.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateThirtyMember" xlink:label="GrantDateThirtyMember" xlink:title="GrantDateThirtyMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateThirtyMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateThirtyMember" order="27.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateThirtyOneMember" xlink:label="GrantDateThirtyOneMember" xlink:title="GrantDateThirtyOneMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateThirtyOneMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateThirtyOneMember" order="28.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateThirtyTwoMember" xlink:label="GrantDateThirtyTwoMember" xlink:title="GrantDateThirtyTwoMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateThirtyTwoMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateThirtyTwoMember" order="29.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateThirtyThreeMember" xlink:label="GrantDateThirtyThreeMember" xlink:title="GrantDateThirtyThreeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateThirtyThreeMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateThirtyThreeMember" order="30.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateThirtyFourMember" xlink:label="GrantDateThirtyFourMember" xlink:title="GrantDateThirtyFourMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateThirtyFourMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateThirtyFourMember" order="31.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateThirtyFiveMember" xlink:label="GrantDateThirtyFiveMember" xlink:title="GrantDateThirtyFiveMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateThirtyFiveMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateThirtyFiveMember" order="32.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateThirtySixMember" xlink:label="GrantDateThirtySixMember" xlink:title="GrantDateThirtySixMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateThirtySixMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateThirtySixMember" order="33.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateThirtySevenMember" xlink:label="GrantDateThirtySevenMember" xlink:title="GrantDateThirtySevenMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateThirtySevenMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateThirtySevenMember" order="34.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateThirtyEightMember" xlink:label="GrantDateThirtyEightMember" xlink:title="GrantDateThirtyEightMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateThirtyEightMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateThirtyEightMember" order="35.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateThirtyNineMember" xlink:label="GrantDateThirtyNineMember" xlink:title="GrantDateThirtyNineMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateThirtyNineMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateThirtyNineMember" order="36.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateFortyMember" xlink:label="GrantDateFortyMember" xlink:title="GrantDateFortyMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateFortyMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateFortyMember" order="37.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GrantDateFortyOneMember" xlink:label="GrantDateFortyOneMember" xlink:title="GrantDateFortyOneMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DefaultFinancialStatementsDateMember" xlink:to="GrantDateFortyOneMember" xlink:title="definition: DefaultFinancialStatementsDateMember to GrantDateFortyOneMember" order="38.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:to="RangeAxis" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable to RangeAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="RangeDomain" xlink:title="RangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeDomain" xlink:title="definition: RangeAxis to RangeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="RangeDomain_2" xlink:title="RangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeDomain_2" xlink:title="definition: RangeAxis to RangeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BottomOfRangeMember" xlink:label="BottomOfRangeMember" xlink:title="BottomOfRangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeDomain" xlink:to="BottomOfRangeMember" xlink:title="definition: RangeDomain to BottomOfRangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TopOfRangeMember" xlink:label="TopOfRangeMember" xlink:title="TopOfRangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeDomain" xlink:to="TopOfRangeMember" xlink:title="definition: RangeDomain to TopOfRangeMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/SharebasedPaymentsFairValueOfGrantDateInputsForOptionsGrantedDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:label="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:title="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ShareBasedCompensationArrangementGrantDateFairValueAssumptionsAbstract" xlink:label="ShareBasedCompensationArrangementGrantDateFairValueAssumptionsAbstract" xlink:title="ShareBasedCompensationArrangementGrantDateFairValueAssumptionsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ShareBasedCompensationArrangementGrantDateFairValueAssumptionsAbstract" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to ShareBasedCompensationArrangementGrantDateFairValueAssumptionsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_FairValueOfStockOptionsGranted" xlink:label="FairValueOfStockOptionsGranted" xlink:title="FairValueOfStockOptionsGranted" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="FairValueOfStockOptionsGranted" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to FairValueOfStockOptionsGranted" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ConsiderationShareOptionsGranted" xlink:label="ConsiderationShareOptionsGranted" xlink:title="ConsiderationShareOptionsGranted" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ConsiderationShareOptionsGranted" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to ConsiderationShareOptionsGranted" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ExercisePriceShareOptionsGranted2019" xlink:label="ExercisePriceShareOptionsGranted2019" xlink:title="ExercisePriceShareOptionsGranted2019" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ExercisePriceShareOptionsGranted2019" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to ExercisePriceShareOptionsGranted2019" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DateOfGrantOfSharebasedPaymentArrangement" xlink:label="DateOfGrantOfSharebasedPaymentArrangement" xlink:title="DateOfGrantOfSharebasedPaymentArrangement" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="DateOfGrantOfSharebasedPaymentArrangement" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to DateOfGrantOfSharebasedPaymentArrangement" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DateOfExpiryShareBasedPaymentArrangement" xlink:label="DateOfExpiryShareBasedPaymentArrangement" xlink:title="DateOfExpiryShareBasedPaymentArrangement" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="DateOfExpiryShareBasedPaymentArrangement" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to DateOfExpiryShareBasedPaymentArrangement" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DescriptionOfOptionLifeShareOptionsGranted" xlink:label="DescriptionOfOptionLifeShareOptionsGranted" xlink:title="DescriptionOfOptionLifeShareOptionsGranted" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="DescriptionOfOptionLifeShareOptionsGranted" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to DescriptionOfOptionLifeShareOptionsGranted" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_WeightedAverageSharePriceShareOptionsGranted2019" xlink:label="WeightedAverageSharePriceShareOptionsGranted2019" xlink:title="WeightedAverageSharePriceShareOptionsGranted2019" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="WeightedAverageSharePriceShareOptionsGranted2019" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to WeightedAverageSharePriceShareOptionsGranted2019" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DescriptionOfExpectedVolatilityShareOptionsGranted" xlink:label="DescriptionOfExpectedVolatilityShareOptionsGranted" xlink:title="DescriptionOfExpectedVolatilityShareOptionsGranted" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="DescriptionOfExpectedVolatilityShareOptionsGranted" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to DescriptionOfExpectedVolatilityShareOptionsGranted" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ExpectedDividendAsPercentageShareOptionsGranted" xlink:label="ExpectedDividendAsPercentageShareOptionsGranted" xlink:title="ExpectedDividendAsPercentageShareOptionsGranted" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ExpectedDividendAsPercentageShareOptionsGranted" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to ExpectedDividendAsPercentageShareOptionsGranted" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DescriptionOfRiskFreeInterestRateShareOptionsGranted" xlink:label="DescriptionOfRiskFreeInterestRateShareOptionsGranted" xlink:title="DescriptionOfRiskFreeInterestRateShareOptionsGranted" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="DescriptionOfRiskFreeInterestRateShareOptionsGranted" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to DescriptionOfRiskFreeInterestRateShareOptionsGranted" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantedPercentage" xlink:label="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantedPercentage" xlink:title="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantedPercentage" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantedPercentage" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantedPercentage" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:label="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:title="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems" xlink:to="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementLineItems to DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" order="13.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfSharebasedPaymentArrangementsAxis" xlink:label="TypesOfSharebasedPaymentArrangementsAxis" xlink:title="TypesOfSharebasedPaymentArrangementsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:to="TypesOfSharebasedPaymentArrangementsAxis" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable to TypesOfSharebasedPaymentArrangementsAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:label="TypesOfSharebasedPaymentArrangementsDomain" xlink:title="TypesOfSharebasedPaymentArrangementsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TypesOfSharebasedPaymentArrangementsAxis" xlink:to="TypesOfSharebasedPaymentArrangementsDomain" xlink:title="definition: TypesOfSharebasedPaymentArrangementsAxis to TypesOfSharebasedPaymentArrangementsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfSharebasedPaymentArrangementsDomain" xlink:label="TypesOfSharebasedPaymentArrangementsDomain_2" xlink:title="TypesOfSharebasedPaymentArrangementsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TypesOfSharebasedPaymentArrangementsAxis" xlink:to="TypesOfSharebasedPaymentArrangementsDomain_2" xlink:title="definition: TypesOfSharebasedPaymentArrangementsAxis to TypesOfSharebasedPaymentArrangementsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ShareOptionsMember" xlink:label="ShareOptionsMember" xlink:title="ShareOptionsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TypesOfSharebasedPaymentArrangementsDomain" xlink:to="ShareOptionsMember" xlink:title="definition: TypesOfSharebasedPaymentArrangementsDomain to ShareOptionsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable" xlink:to="RangeAxis" xlink:title="definition: DisclosureOfTermsAndConditionsOfSharebasedPaymentArrangementTable to RangeAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="RangeDomain" xlink:title="RangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeDomain" xlink:title="definition: RangeAxis to RangeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="RangeDomain_2" xlink:title="RangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeDomain_2" xlink:title="definition: RangeAxis to RangeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BottomOfRangeMember" xlink:label="BottomOfRangeMember" xlink:title="BottomOfRangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeDomain" xlink:to="BottomOfRangeMember" xlink:title="definition: RangeDomain to BottomOfRangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TopOfRangeMember" xlink:label="TopOfRangeMember" xlink:title="TopOfRangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeDomain" xlink:to="TopOfRangeMember" xlink:title="definition: RangeDomain to TopOfRangeMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/CashFlowInformationDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/FinancialRiskManagementForeignCurrencyRiskDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:label="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:title="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ForeignCurrencyRiskAbstract" xlink:label="ForeignCurrencyRiskAbstract" xlink:title="ForeignCurrencyRiskAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ForeignCurrencyRiskAbstract" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to ForeignCurrencyRiskAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ImpactOnPostTaxProfitLossAbstract" xlink:label="ImpactOnPostTaxProfitLossAbstract" xlink:title="ImpactOnPostTaxProfitLossAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ImpactOnPostTaxProfitLossAbstract" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to ImpactOnPostTaxProfitLossAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GainsLossesOnChangeInValueOfForeignCurrencyBasisSpreadsNetOfTax" xlink:label="GainsLossesOnChangeInValueOfForeignCurrencyBasisSpreadsNetOfTax" xlink:title="GainsLossesOnChangeInValueOfForeignCurrencyBasisSpreadsNetOfTax" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="GainsLossesOnChangeInValueOfForeignCurrencyBasisSpreadsNetOfTax" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to GainsLossesOnChangeInValueOfForeignCurrencyBasisSpreadsNetOfTax" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ReserveOfExchangeDifferencesOnTranslation" xlink:label="ReserveOfExchangeDifferencesOnTranslation" xlink:title="ReserveOfExchangeDifferencesOnTranslation" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ReserveOfExchangeDifferencesOnTranslation" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to ReserveOfExchangeDifferencesOnTranslation" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AllowanceForCreditLossesOfFinancialAssets" xlink:label="AllowanceForCreditLossesOfFinancialAssets" xlink:title="AllowanceForCreditLossesOfFinancialAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="AllowanceForCreditLossesOfFinancialAssets" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to AllowanceForCreditLossesOfFinancialAssets" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_SurplusOfForeignCurrencyReceivablesAndFinancialAssetsOverPayables" xlink:label="SurplusOfForeignCurrencyReceivablesAndFinancialAssetsOverPayables" xlink:title="SurplusOfForeignCurrencyReceivablesAndFinancialAssetsOverPayables" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="SurplusOfForeignCurrencyReceivablesAndFinancialAssetsOverPayables" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to SurplusOfForeignCurrencyReceivablesAndFinancialAssetsOverPayables" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PercentageOfCashHeldInForeignCurrency" xlink:label="PercentageOfCashHeldInForeignCurrency" xlink:title="PercentageOfCashHeldInForeignCurrency" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="PercentageOfCashHeldInForeignCurrency" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to PercentageOfCashHeldInForeignCurrency" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashAndCashEquivalents" xlink:label="CashAndCashEquivalents" xlink:title="CashAndCashEquivalents" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="CashAndCashEquivalents" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to CashAndCashEquivalents" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TradeReceivables" xlink:label="TradeReceivables" xlink:title="TradeReceivables" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="TradeReceivables" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to TradeReceivables" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinancialAssets" xlink:label="FinancialAssets" xlink:title="FinancialAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="FinancialAssets" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to FinancialAssets" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TradeAndOtherPayablesToTradeSuppliers" xlink:label="TradeAndOtherPayablesToTradeSuppliers" xlink:title="TradeAndOtherPayablesToTradeSuppliers" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="TradeAndOtherPayablesToTradeSuppliers" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to TradeAndOtherPayablesToTradeSuppliers" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_GovernmentGrants" xlink:label="GovernmentGrants" xlink:title="GovernmentGrants" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="GovernmentGrants" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to GovernmentGrants" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProvisionForDecommissioningRestorationAndRehabilitationCosts" xlink:label="ProvisionForDecommissioningRestorationAndRehabilitationCosts" xlink:title="ProvisionForDecommissioningRestorationAndRehabilitationCosts" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ProvisionForDecommissioningRestorationAndRehabilitationCosts" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to ProvisionForDecommissioningRestorationAndRehabilitationCosts" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ContingentConsideration" xlink:label="ContingentConsideration" xlink:title="ContingentConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ContingentConsideration" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to ContingentConsideration" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Borrowings" xlink:label="Borrowings" xlink:title="Borrowings" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="Borrowings" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to Borrowings" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:label="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:title="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" order="16.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfRisksAxis" xlink:label="TypesOfRisksAxis" xlink:title="TypesOfRisksAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:to="TypesOfRisksAxis" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable to TypesOfRisksAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfRisksDomain" xlink:label="TypesOfRisksDomain" xlink:title="TypesOfRisksDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TypesOfRisksAxis" xlink:to="TypesOfRisksDomain" xlink:title="definition: TypesOfRisksAxis to TypesOfRisksDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfRisksDomain" xlink:label="TypesOfRisksDomain_2" xlink:title="TypesOfRisksDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TypesOfRisksAxis" xlink:to="TypesOfRisksDomain_2" xlink:title="definition: TypesOfRisksAxis to TypesOfRisksDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrencyRiskMember" xlink:label="CurrencyRiskMember" xlink:title="CurrencyRiskMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TypesOfRisksDomain" xlink:to="CurrencyRiskMember" xlink:title="definition: TypesOfRisksDomain to CurrencyRiskMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_CurrencyRiskIncreaseThroughForeignExchangeRatesMember" xlink:label="CurrencyRiskIncreaseThroughForeignExchangeRatesMember" xlink:title="CurrencyRiskIncreaseThroughForeignExchangeRatesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CurrencyRiskMember" xlink:to="CurrencyRiskIncreaseThroughForeignExchangeRatesMember" xlink:title="definition: CurrencyRiskMember to CurrencyRiskIncreaseThroughForeignExchangeRatesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_CurrencyRiskDecreaseThroughForeignExchangeRatesMember" xlink:label="CurrencyRiskDecreaseThroughForeignExchangeRatesMember" xlink:title="CurrencyRiskDecreaseThroughForeignExchangeRatesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CurrencyRiskMember" xlink:to="CurrencyRiskDecreaseThroughForeignExchangeRatesMember" xlink:title="definition: CurrencyRiskMember to CurrencyRiskDecreaseThroughForeignExchangeRatesMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CreditRiskMember" xlink:label="CreditRiskMember" xlink:title="CreditRiskMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CurrencyRiskMember" xlink:to="CreditRiskMember" xlink:title="definition: CurrencyRiskMember to CreditRiskMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_CurrencyAxis" xlink:label="CurrencyAxis" xlink:title="CurrencyAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:to="CurrencyAxis" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable to CurrencyAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/currency/2024/currency-2024.xsd#currency_AllCurrenciesDomain" xlink:label="AllCurrenciesDomain" xlink:title="AllCurrenciesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="CurrencyAxis" xlink:to="AllCurrenciesDomain" xlink:title="definition: CurrencyAxis to AllCurrenciesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/currency/2024/currency-2024.xsd#currency_AllCurrenciesDomain" xlink:label="AllCurrenciesDomain_2" xlink:title="AllCurrenciesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="CurrencyAxis" xlink:to="AllCurrenciesDomain_2" xlink:title="definition: CurrencyAxis to AllCurrenciesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/currency/2024/currency-2024.xsd#currency_USD" xlink:label="USD" xlink:title="USD" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllCurrenciesDomain" xlink:to="USD" xlink:title="definition: AllCurrenciesDomain to USD" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/currency/2024/currency-2024.xsd#currency_AUD" xlink:label="AUD" xlink:title="AUD" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllCurrenciesDomain" xlink:to="AUD" xlink:title="definition: AllCurrenciesDomain to AUD" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/currency/2024/currency-2024.xsd#currency_EUR" xlink:label="EUR" xlink:title="EUR" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllCurrenciesDomain" xlink:to="EUR" xlink:title="definition: AllCurrenciesDomain to EUR" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/currency/2024/currency-2024.xsd#currency_CHF" xlink:label="CHF" xlink:title="CHF" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllCurrenciesDomain" xlink:to="CHF" xlink:title="definition: AllCurrenciesDomain to CHF" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/currency/2024/currency-2024.xsd#currency_JPY" xlink:label="JPY" xlink:title="JPY" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllCurrenciesDomain" xlink:to="JPY" xlink:title="definition: AllCurrenciesDomain to JPY" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/currency/2024/currency-2024.xsd#currency_GBP" xlink:label="GBP" xlink:title="GBP" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllCurrenciesDomain" xlink:to="GBP" xlink:title="definition: AllCurrenciesDomain to GBP" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/currency/2024/currency-2024.xsd#currency_CAD" xlink:label="CAD" xlink:title="CAD" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllCurrenciesDomain" xlink:to="CAD" xlink:title="definition: AllCurrenciesDomain to CAD" order="7.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/FinancialRiskManagementCreditRiskDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:label="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:title="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AgeingOfTradeReceivablesAbstract" xlink:label="AgeingOfTradeReceivablesAbstract" xlink:title="AgeingOfTradeReceivablesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="AgeingOfTradeReceivablesAbstract" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to AgeingOfTradeReceivablesAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ConcentrationOfCreditRiskAbstract" xlink:label="ConcentrationOfCreditRiskAbstract" xlink:title="ConcentrationOfCreditRiskAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="ConcentrationOfCreditRiskAbstract" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to ConcentrationOfCreditRiskAbstract" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_NumberOfDistributors" xlink:label="NumberOfDistributors" xlink:title="NumberOfDistributors" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="NumberOfDistributors" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to NumberOfDistributors" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PercentageOfCreditRisk" xlink:label="PercentageOfCreditRisk" xlink:title="PercentageOfCreditRisk" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="PercentageOfCreditRisk" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to PercentageOfCreditRisk" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PercentageOfMajorCreditRisk" xlink:label="PercentageOfMajorCreditRisk" xlink:title="PercentageOfMajorCreditRisk" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="PercentageOfMajorCreditRisk" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to PercentageOfMajorCreditRisk" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AllowanceForCreditLossesOfFinancialAssets" xlink:label="AllowanceForCreditLossesOfFinancialAssets" xlink:title="AllowanceForCreditLossesOfFinancialAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="AllowanceForCreditLossesOfFinancialAssets" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to AllowanceForCreditLossesOfFinancialAssets" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TradeReceivables" xlink:label="TradeReceivables" xlink:title="TradeReceivables" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="TradeReceivables" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to TradeReceivables" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:label="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:title="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems" xlink:to="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsLineItems to DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" order="8.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfRisksAxis" xlink:label="TypesOfRisksAxis" xlink:title="TypesOfRisksAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:to="TypesOfRisksAxis" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable to TypesOfRisksAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfRisksDomain" xlink:label="TypesOfRisksDomain" xlink:title="TypesOfRisksDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TypesOfRisksAxis" xlink:to="TypesOfRisksDomain" xlink:title="definition: TypesOfRisksAxis to TypesOfRisksDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TypesOfRisksDomain" xlink:label="TypesOfRisksDomain_2" xlink:title="TypesOfRisksDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TypesOfRisksAxis" xlink:to="TypesOfRisksDomain_2" xlink:title="definition: TypesOfRisksAxis to TypesOfRisksDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CreditRiskMember" xlink:label="CreditRiskMember" xlink:title="CreditRiskMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TypesOfRisksDomain" xlink:to="CreditRiskMember" xlink:title="definition: TypesOfRisksDomain to CreditRiskMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PastDueStatusAxis" xlink:label="PastDueStatusAxis" xlink:title="PastDueStatusAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable" xlink:to="PastDueStatusAxis" xlink:title="definition: DisclosureOfNatureAndExtentOfRisksArisingFromFinancialInstrumentsTable to PastDueStatusAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PastDueStatusDomain" xlink:label="PastDueStatusDomain" xlink:title="PastDueStatusDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="PastDueStatusAxis" xlink:to="PastDueStatusDomain" xlink:title="definition: PastDueStatusAxis to PastDueStatusDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PastDueStatusDomain" xlink:label="PastDueStatusDomain_2" xlink:title="PastDueStatusDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="PastDueStatusAxis" xlink:to="PastDueStatusDomain_2" xlink:title="definition: PastDueStatusAxis to PastDueStatusDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CurrentMember" xlink:label="CurrentMember" xlink:title="CurrentMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PastDueStatusDomain" xlink:to="CurrentMember" xlink:title="definition: PastDueStatusDomain to CurrentMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LaterThanOneMonthAndNotLaterThanTwoMonthsMember" xlink:label="LaterThanOneMonthAndNotLaterThanTwoMonthsMember" xlink:title="LaterThanOneMonthAndNotLaterThanTwoMonthsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PastDueStatusDomain" xlink:to="LaterThanOneMonthAndNotLaterThanTwoMonthsMember" xlink:title="definition: PastDueStatusDomain to LaterThanOneMonthAndNotLaterThanTwoMonthsMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LaterThanTwoMonthsAndNotLaterThanThreeMonthsMember" xlink:label="LaterThanTwoMonthsAndNotLaterThanThreeMonthsMember" xlink:title="LaterThanTwoMonthsAndNotLaterThanThreeMonthsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PastDueStatusDomain" xlink:to="LaterThanTwoMonthsAndNotLaterThanThreeMonthsMember" xlink:title="definition: PastDueStatusDomain to LaterThanTwoMonthsAndNotLaterThanThreeMonthsMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LaterThanThreeMonthsAndNotLaterThanFourMonthsMember" xlink:label="LaterThanThreeMonthsAndNotLaterThanFourMonthsMember" xlink:title="LaterThanThreeMonthsAndNotLaterThanFourMonthsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PastDueStatusDomain" xlink:to="LaterThanThreeMonthsAndNotLaterThanFourMonthsMember" xlink:title="definition: PastDueStatusDomain to LaterThanThreeMonthsAndNotLaterThanFourMonthsMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LaterThanFourMonthsMember" xlink:label="LaterThanFourMonthsMember" xlink:title="LaterThanFourMonthsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PastDueStatusDomain" xlink:to="LaterThanFourMonthsMember" xlink:title="definition: PastDueStatusDomain to LaterThanFourMonthsMember" order="5.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/FinancialRiskManagementRemainingContractualMaturitiesDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems" xlink:label="DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems" xlink:title="DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesAbstract" xlink:label="DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesAbstract" xlink:title="DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems" xlink:to="DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesAbstract" xlink:title="definition: DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems to DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NonderivativeFinancialLiabilitiesUndiscountedCashFlows" xlink:label="NonderivativeFinancialLiabilitiesUndiscountedCashFlows" xlink:title="NonderivativeFinancialLiabilitiesUndiscountedCashFlows" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems" xlink:to="NonderivativeFinancialLiabilitiesUndiscountedCashFlows" xlink:title="definition: DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems to NonderivativeFinancialLiabilitiesUndiscountedCashFlows" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TradeAndOtherCurrentPayables" xlink:label="TradeAndOtherCurrentPayables" xlink:title="TradeAndOtherCurrentPayables" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems" xlink:to="TradeAndOtherCurrentPayables" xlink:title="definition: DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems to TradeAndOtherCurrentPayables" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Borrowings" xlink:label="Borrowings" xlink:title="Borrowings" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems" xlink:to="Borrowings" xlink:title="definition: DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems to Borrowings" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LeaseLiabilities" xlink:label="LeaseLiabilities" xlink:title="LeaseLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems" xlink:to="LeaseLiabilities" xlink:title="definition: DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems to LeaseLiabilities" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Provisions" xlink:label="Provisions" xlink:title="Provisions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems" xlink:to="Provisions" xlink:title="definition: DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems to Provisions" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ContingentConsideration" xlink:label="ContingentConsideration" xlink:title="ContingentConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems" xlink:to="ContingentConsideration" xlink:title="definition: DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems to ContingentConsideration" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_FinancialLiabilities" xlink:label="FinancialLiabilities" xlink:title="FinancialLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems" xlink:to="FinancialLiabilities" xlink:title="definition: DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems to FinancialLiabilities" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesTable" xlink:label="DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesTable" xlink:title="DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems" xlink:to="DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesTable" xlink:title="definition: DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesLineItems to DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesTable" order="9.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MaturityAxis" xlink:label="MaturityAxis" xlink:title="MaturityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesTable" xlink:to="MaturityAxis" xlink:title="definition: DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesTable to MaturityAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MaturityDomain" xlink:label="MaturityDomain" xlink:title="MaturityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="MaturityAxis" xlink:to="MaturityDomain" xlink:title="definition: MaturityAxis to MaturityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MaturityDomain" xlink:label="MaturityDomain_2" xlink:title="MaturityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="MaturityAxis" xlink:to="MaturityDomain_2" xlink:title="definition: MaturityAxis to MaturityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LaterThanOneMonthAndNotLaterThanSixMonthsMember" xlink:label="LaterThanOneMonthAndNotLaterThanSixMonthsMember" xlink:title="LaterThanOneMonthAndNotLaterThanSixMonthsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MaturityDomain" xlink:to="LaterThanOneMonthAndNotLaterThanSixMonthsMember" xlink:title="definition: MaturityDomain to LaterThanOneMonthAndNotLaterThanSixMonthsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LaterThanSixMonthsAndNotLaterThanOneYearMember" xlink:label="LaterThanSixMonthsAndNotLaterThanOneYearMember" xlink:title="LaterThanSixMonthsAndNotLaterThanOneYearMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MaturityDomain" xlink:to="LaterThanSixMonthsAndNotLaterThanOneYearMember" xlink:title="definition: MaturityDomain to LaterThanSixMonthsAndNotLaterThanOneYearMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LaterThanOneYearAndNotLaterThanFiveYearsMember" xlink:label="LaterThanOneYearAndNotLaterThanFiveYearsMember" xlink:title="LaterThanOneYearAndNotLaterThanFiveYearsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MaturityDomain" xlink:to="LaterThanOneYearAndNotLaterThanFiveYearsMember" xlink:title="definition: MaturityDomain to LaterThanOneYearAndNotLaterThanFiveYearsMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LaterThanFiveYearsMember" xlink:label="LaterThanFiveYearsMember" xlink:title="LaterThanFiveYearsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MaturityDomain" xlink:to="LaterThanFiveYearsMember" xlink:title="definition: MaturityDomain to LaterThanFiveYearsMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfFinancialInstrumentsAxis" xlink:label="ClassesOfFinancialInstrumentsAxis" xlink:title="ClassesOfFinancialInstrumentsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesTable" xlink:to="ClassesOfFinancialInstrumentsAxis" xlink:title="definition: DisclosureOfMaturityAnalysisForNonderivativeFinancialLiabilitiesTable to ClassesOfFinancialInstrumentsAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfFinancialInstrumentsDomain" xlink:label="ClassesOfFinancialInstrumentsDomain" xlink:title="ClassesOfFinancialInstrumentsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ClassesOfFinancialInstrumentsAxis" xlink:to="ClassesOfFinancialInstrumentsDomain" xlink:title="definition: ClassesOfFinancialInstrumentsAxis to ClassesOfFinancialInstrumentsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ClassesOfFinancialInstrumentsDomain" xlink:label="ClassesOfFinancialInstrumentsDomain_2" xlink:title="ClassesOfFinancialInstrumentsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ClassesOfFinancialInstrumentsAxis" xlink:to="ClassesOfFinancialInstrumentsDomain_2" xlink:title="definition: ClassesOfFinancialInstrumentsAxis to ClassesOfFinancialInstrumentsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TradeAndOtherPayablesMember" xlink:label="TradeAndOtherPayablesMember" xlink:title="TradeAndOtherPayablesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfFinancialInstrumentsDomain" xlink:to="TradeAndOtherPayablesMember" xlink:title="definition: ClassesOfFinancialInstrumentsDomain to TradeAndOtherPayablesMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_BorrowingMember" xlink:label="BorrowingMember" xlink:title="BorrowingMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfFinancialInstrumentsDomain" xlink:to="BorrowingMember" xlink:title="definition: ClassesOfFinancialInstrumentsDomain to BorrowingMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LeaseLiabilitiesMember" xlink:label="LeaseLiabilitiesMember" xlink:title="LeaseLiabilitiesMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfFinancialInstrumentsDomain" xlink:to="LeaseLiabilitiesMember" xlink:title="definition: ClassesOfFinancialInstrumentsDomain to LeaseLiabilitiesMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GovernmentGrantLiabilityMember" xlink:label="GovernmentGrantLiabilityMember" xlink:title="GovernmentGrantLiabilityMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfFinancialInstrumentsDomain" xlink:to="GovernmentGrantLiabilityMember" xlink:title="definition: ClassesOfFinancialInstrumentsDomain to GovernmentGrantLiabilityMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ContingentConsiderationMember" xlink:label="ContingentConsiderationMember" xlink:title="ContingentConsiderationMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ClassesOfFinancialInstrumentsDomain" xlink:to="ContingentConsiderationMember" xlink:title="definition: ClassesOfFinancialInstrumentsDomain to ContingentConsiderationMember" order="5.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/FinancialRiskManagementFairValueDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsLineItems" xlink:label="DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsLineItems" xlink:title="DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsAbstract" xlink:label="DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsAbstract" xlink:title="DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsLineItems" xlink:to="DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsAbstract" xlink:title="definition: DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsLineItems to DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PercentageOfReasonablyPossibleIncreaseInUnobservableInputAssets" xlink:label="PercentageOfReasonablyPossibleIncreaseInUnobservableInputAssets" xlink:title="PercentageOfReasonablyPossibleIncreaseInUnobservableInputAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsLineItems" xlink:to="PercentageOfReasonablyPossibleIncreaseInUnobservableInputAssets" xlink:title="definition: DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsLineItems to PercentageOfReasonablyPossibleIncreaseInUnobservableInputAssets" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseInFairValueMeasurementDueToReasonablyPossibleIncreaseInUnobservableInputRecognisedInOtherComprehensiveIncomeAfterTaxAssets" xlink:label="IncreaseDecreaseInFairValueMeasurementDueToReasonablyPossibleIncreaseInUnobservableInputRecognisedInOtherComprehensiveIncomeAfterTaxAssets" xlink:title="IncreaseDecreaseInFairValueMeasurementDueToReasonablyPossibleIncreaseInUnobservableInputRecognisedInOtherComprehensiveIncomeAfterTaxAssets" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsLineItems" xlink:to="IncreaseDecreaseInFairValueMeasurementDueToReasonablyPossibleIncreaseInUnobservableInputRecognisedInOtherComprehensiveIncomeAfterTaxAssets" xlink:title="definition: DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsLineItems to IncreaseDecreaseInFairValueMeasurementDueToReasonablyPossibleIncreaseInUnobservableInputRecognisedInOtherComprehensiveIncomeAfterTaxAssets" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_PercentageOfReasonablyPossibleIncreaseInUnobservableInputLiabilities" xlink:label="PercentageOfReasonablyPossibleIncreaseInUnobservableInputLiabilities" xlink:title="PercentageOfReasonablyPossibleIncreaseInUnobservableInputLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsLineItems" xlink:to="PercentageOfReasonablyPossibleIncreaseInUnobservableInputLiabilities" xlink:title="definition: DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsLineItems to PercentageOfReasonablyPossibleIncreaseInUnobservableInputLiabilities" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncreaseDecreaseInFairValueMeasurementDueToReasonablyPossibleIncreaseInUnobservableInputRecognisedInProfitOrLossBeforeTaxLiabilities" xlink:label="IncreaseDecreaseInFairValueMeasurementDueToReasonablyPossibleIncreaseInUnobservableInputRecognisedInProfitOrLossBeforeTaxLiabilities" xlink:title="IncreaseDecreaseInFairValueMeasurementDueToReasonablyPossibleIncreaseInUnobservableInputRecognisedInProfitOrLossBeforeTaxLiabilities" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsLineItems" xlink:to="IncreaseDecreaseInFairValueMeasurementDueToReasonablyPossibleIncreaseInUnobservableInputRecognisedInProfitOrLossBeforeTaxLiabilities" xlink:title="definition: DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsLineItems to IncreaseDecreaseInFairValueMeasurementDueToReasonablyPossibleIncreaseInUnobservableInputRecognisedInProfitOrLossBeforeTaxLiabilities" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsTable" xlink:label="DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsTable" xlink:title="DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsLineItems" xlink:to="DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsTable" xlink:title="definition: DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsLineItems to DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsTable" order="6.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LevelsOfFairValueHierarchyAxis" xlink:label="LevelsOfFairValueHierarchyAxis" xlink:title="LevelsOfFairValueHierarchyAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsTable" xlink:to="LevelsOfFairValueHierarchyAxis" xlink:title="definition: DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsTable to LevelsOfFairValueHierarchyAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LevelsOfFairValueHierarchyDomain" xlink:label="LevelsOfFairValueHierarchyDomain" xlink:title="LevelsOfFairValueHierarchyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="LevelsOfFairValueHierarchyAxis" xlink:to="LevelsOfFairValueHierarchyDomain" xlink:title="definition: LevelsOfFairValueHierarchyAxis to LevelsOfFairValueHierarchyDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LevelsOfFairValueHierarchyDomain" xlink:label="LevelsOfFairValueHierarchyDomain_2" xlink:title="LevelsOfFairValueHierarchyDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="LevelsOfFairValueHierarchyAxis" xlink:to="LevelsOfFairValueHierarchyDomain_2" xlink:title="definition: LevelsOfFairValueHierarchyAxis to LevelsOfFairValueHierarchyDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Level1OfFairValueHierarchyMember" xlink:label="Level1OfFairValueHierarchyMember" xlink:title="Level1OfFairValueHierarchyMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LevelsOfFairValueHierarchyDomain" xlink:to="Level1OfFairValueHierarchyMember" xlink:title="definition: LevelsOfFairValueHierarchyDomain to Level1OfFairValueHierarchyMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_Level3OfFairValueHierarchyMember" xlink:label="Level3OfFairValueHierarchyMember" xlink:title="Level3OfFairValueHierarchyMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="LevelsOfFairValueHierarchyDomain" xlink:to="Level3OfFairValueHierarchyMember" xlink:title="definition: LevelsOfFairValueHierarchyDomain to Level3OfFairValueHierarchyMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ValuationTechniquesUsedInFairValueMeasurementAxis" xlink:label="ValuationTechniquesUsedInFairValueMeasurementAxis" xlink:title="ValuationTechniquesUsedInFairValueMeasurementAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsTable" xlink:to="ValuationTechniquesUsedInFairValueMeasurementAxis" xlink:title="definition: DisclosureOfSensitivityAnalysisOfFairValueMeasurementToChangesInUnobservableInputsAssetsTable to ValuationTechniquesUsedInFairValueMeasurementAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ValuationTechniquesUsedInFairValueMeasurementDomain" xlink:label="ValuationTechniquesUsedInFairValueMeasurementDomain" xlink:title="ValuationTechniquesUsedInFairValueMeasurementDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="ValuationTechniquesUsedInFairValueMeasurementAxis" xlink:to="ValuationTechniquesUsedInFairValueMeasurementDomain" xlink:title="definition: ValuationTechniquesUsedInFairValueMeasurementAxis to ValuationTechniquesUsedInFairValueMeasurementDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ValuationTechniquesUsedInFairValueMeasurementDomain" xlink:label="ValuationTechniquesUsedInFairValueMeasurementDomain_2" xlink:title="ValuationTechniquesUsedInFairValueMeasurementDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="ValuationTechniquesUsedInFairValueMeasurementAxis" xlink:to="ValuationTechniquesUsedInFairValueMeasurementDomain_2" xlink:title="definition: ValuationTechniquesUsedInFairValueMeasurementAxis to ValuationTechniquesUsedInFairValueMeasurementDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MarketApproachMember" xlink:label="MarketApproachMember" xlink:title="MarketApproachMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ValuationTechniquesUsedInFairValueMeasurementDomain" xlink:to="MarketApproachMember" xlink:title="definition: ValuationTechniquesUsedInFairValueMeasurementDomain to MarketApproachMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IncomeApproachMember" xlink:label="IncomeApproachMember" xlink:title="IncomeApproachMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ValuationTechniquesUsedInFairValueMeasurementDomain" xlink:to="IncomeApproachMember" xlink:title="definition: ValuationTechniquesUsedInFairValueMeasurementDomain to IncomeApproachMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DiscountedCashFlowMember" xlink:label="DiscountedCashFlowMember" xlink:title="DiscountedCashFlowMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="IncomeApproachMember" xlink:to="DiscountedCashFlowMember" xlink:title="definition: IncomeApproachMember to DiscountedCashFlowMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/ContingentLiabilitiesDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/CommitmentsDetails">
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_CommitmentsAndContingenciesLineItems" xlink:label="CommitmentsAndContingenciesLineItems" xlink:title="CommitmentsAndContingenciesLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CapitalCommitmentsAbstract" xlink:label="CapitalCommitmentsAbstract" xlink:title="CapitalCommitmentsAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CommitmentsAndContingenciesLineItems" xlink:to="CapitalCommitmentsAbstract" xlink:title="definition: CommitmentsAndContingenciesLineItems to CapitalCommitmentsAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ContractualCapitalCommitments" xlink:label="ContractualCapitalCommitments" xlink:title="ContractualCapitalCommitments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CommitmentsAndContingenciesLineItems" xlink:to="ContractualCapitalCommitments" xlink:title="definition: CommitmentsAndContingenciesLineItems to ContractualCapitalCommitments" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ResearchAndDevelopmentsCommitmentsContractualObligations" xlink:label="ResearchAndDevelopmentsCommitmentsContractualObligations" xlink:title="ResearchAndDevelopmentsCommitmentsContractualObligations" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CommitmentsAndContingenciesLineItems" xlink:to="ResearchAndDevelopmentsCommitmentsContractualObligations" xlink:title="definition: CommitmentsAndContingenciesLineItems to ResearchAndDevelopmentsCommitmentsContractualObligations" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CapitalCommitments" xlink:label="CapitalCommitments" xlink:title="CapitalCommitments" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="CommitmentsAndContingenciesLineItems" xlink:to="CapitalCommitments" xlink:title="definition: CommitmentsAndContingenciesLineItems to CapitalCommitments" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_CommitmentsAndContingenciesTable" xlink:label="CommitmentsAndContingenciesTable" xlink:title="CommitmentsAndContingenciesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="CommitmentsAndContingenciesLineItems" xlink:to="CommitmentsAndContingenciesTable" xlink:title="definition: CommitmentsAndContingenciesLineItems to CommitmentsAndContingenciesTable" order="5.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MaturityAxis" xlink:label="MaturityAxis" xlink:title="MaturityAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="CommitmentsAndContingenciesTable" xlink:to="MaturityAxis" xlink:title="definition: CommitmentsAndContingenciesTable to MaturityAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MaturityDomain" xlink:label="MaturityDomain" xlink:title="MaturityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="MaturityAxis" xlink:to="MaturityDomain" xlink:title="definition: MaturityAxis to MaturityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_MaturityDomain" xlink:label="MaturityDomain_2" xlink:title="MaturityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="MaturityAxis" xlink:to="MaturityDomain_2" xlink:title="definition: MaturityAxis to MaturityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NotLaterThanOneYearMember" xlink:label="NotLaterThanOneYearMember" xlink:title="NotLaterThanOneYearMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MaturityDomain" xlink:to="NotLaterThanOneYearMember" xlink:title="definition: MaturityDomain to NotLaterThanOneYearMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LaterThanOneYearMember" xlink:label="LaterThanOneYearMember" xlink:title="LaterThanOneYearMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="MaturityDomain" xlink:to="LaterThanOneYearMember" xlink:title="definition: MaturityDomain to LaterThanOneYearMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/RelatedPartyTransactionsKeyManagementPersonnelCompensationDetails" />
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/RelatedPartyTransactionsTransactionsWithOtherRelatedPartiesDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" xlink:label="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" xlink:title="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesAbstract" xlink:label="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesAbstract" xlink:title="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" xlink:to="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesAbstract" xlink:title="definition: DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems to DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_KeyManagementPersonnelPurchasesOfGoodsAndServicesRelatedPartyTransactions" xlink:label="KeyManagementPersonnelPurchasesOfGoodsAndServicesRelatedPartyTransactions" xlink:title="KeyManagementPersonnelPurchasesOfGoodsAndServicesRelatedPartyTransactions" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" xlink:to="KeyManagementPersonnelPurchasesOfGoodsAndServicesRelatedPartyTransactions" xlink:title="definition: DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems to KeyManagementPersonnelPurchasesOfGoodsAndServicesRelatedPartyTransactions" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_KeyManagementPersonnelCompensationConsultingAgreementFeesPaid" xlink:label="KeyManagementPersonnelCompensationConsultingAgreementFeesPaid" xlink:title="KeyManagementPersonnelCompensationConsultingAgreementFeesPaid" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" xlink:to="KeyManagementPersonnelCompensationConsultingAgreementFeesPaid" xlink:title="definition: DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems to KeyManagementPersonnelCompensationConsultingAgreementFeesPaid" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_KeyManagementPersonnelCompensationConsultingFees" xlink:label="KeyManagementPersonnelCompensationConsultingFees" xlink:title="KeyManagementPersonnelCompensationConsultingFees" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" xlink:to="KeyManagementPersonnelCompensationConsultingFees" xlink:title="definition: DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems to KeyManagementPersonnelCompensationConsultingFees" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_UpfrontCashConsideration" xlink:label="UpfrontCashConsideration" xlink:title="UpfrontCashConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" xlink:to="UpfrontCashConsideration" xlink:title="definition: DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems to UpfrontCashConsideration" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_BusinessAcquisitionConsiderationTerm" xlink:label="BusinessAcquisitionConsiderationTerm" xlink:title="BusinessAcquisitionConsiderationTerm" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" xlink:to="BusinessAcquisitionConsiderationTerm" xlink:title="definition: DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems to BusinessAcquisitionConsiderationTerm" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AmountIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntity" xlink:label="AmountIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntity" xlink:title="AmountIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" xlink:to="AmountIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntity" xlink:title="definition: DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems to AmountIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntity" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesTable" xlink:label="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesTable" xlink:title="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" xlink:to="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesTable" xlink:title="definition: DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems to DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesTable" order="8.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SeparateManagementEntitiesAxis" xlink:label="SeparateManagementEntitiesAxis" xlink:title="SeparateManagementEntitiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesTable" xlink:to="SeparateManagementEntitiesAxis" xlink:title="definition: DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesTable to SeparateManagementEntitiesAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SeparateManagementEntitiesDomain" xlink:label="SeparateManagementEntitiesDomain" xlink:title="SeparateManagementEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SeparateManagementEntitiesAxis" xlink:to="SeparateManagementEntitiesDomain" xlink:title="definition: SeparateManagementEntitiesAxis to SeparateManagementEntitiesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SeparateManagementEntitiesDomain" xlink:label="SeparateManagementEntitiesDomain_2" xlink:title="SeparateManagementEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SeparateManagementEntitiesAxis" xlink:to="SeparateManagementEntitiesDomain_2" xlink:title="definition: SeparateManagementEntitiesAxis to SeparateManagementEntitiesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ABXCROMember" xlink:label="ABXCROMember" xlink:title="ABXCROMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SeparateManagementEntitiesDomain" xlink:to="ABXCROMember" xlink:title="definition: SeparateManagementEntitiesDomain to ABXCROMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/RelatedPartyTransactionsInterestsInOtherEntitiesDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTransactionsBetweenRelatedPartiesLineItems" xlink:label="DisclosureOfTransactionsBetweenRelatedPartiesLineItems" xlink:title="DisclosureOfTransactionsBetweenRelatedPartiesLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_InterestsInOtherEntitiesAbstract" xlink:label="InterestsInOtherEntitiesAbstract" xlink:title="InterestsInOtherEntitiesAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTransactionsBetweenRelatedPartiesLineItems" xlink:to="InterestsInOtherEntitiesAbstract" xlink:title="definition: DisclosureOfTransactionsBetweenRelatedPartiesLineItems to InterestsInOtherEntitiesAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CountryOfIncorporationOrResidenceOfSubsidiary" xlink:label="CountryOfIncorporationOrResidenceOfSubsidiary" xlink:title="CountryOfIncorporationOrResidenceOfSubsidiary" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTransactionsBetweenRelatedPartiesLineItems" xlink:to="CountryOfIncorporationOrResidenceOfSubsidiary" xlink:title="definition: DisclosureOfTransactionsBetweenRelatedPartiesLineItems to CountryOfIncorporationOrResidenceOfSubsidiary" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_ProportionOfOwnershipInterestInSubsidiary" xlink:label="ProportionOfOwnershipInterestInSubsidiary" xlink:title="ProportionOfOwnershipInterestInSubsidiary" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfTransactionsBetweenRelatedPartiesLineItems" xlink:to="ProportionOfOwnershipInterestInSubsidiary" xlink:title="definition: DisclosureOfTransactionsBetweenRelatedPartiesLineItems to ProportionOfOwnershipInterestInSubsidiary" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfTransactionsBetweenRelatedPartiesTable" xlink:label="DisclosureOfTransactionsBetweenRelatedPartiesTable" xlink:title="DisclosureOfTransactionsBetweenRelatedPartiesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfTransactionsBetweenRelatedPartiesLineItems" xlink:to="DisclosureOfTransactionsBetweenRelatedPartiesTable" xlink:title="definition: DisclosureOfTransactionsBetweenRelatedPartiesLineItems to DisclosureOfTransactionsBetweenRelatedPartiesTable" order="4.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SignificantInvestmentsInSubsidiariesAxis" xlink:label="SignificantInvestmentsInSubsidiariesAxis" xlink:title="SignificantInvestmentsInSubsidiariesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfTransactionsBetweenRelatedPartiesTable" xlink:to="SignificantInvestmentsInSubsidiariesAxis" xlink:title="definition: DisclosureOfTransactionsBetweenRelatedPartiesTable to SignificantInvestmentsInSubsidiariesAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SignificantInvestmentsInSubsidiariesDomain" xlink:label="SignificantInvestmentsInSubsidiariesDomain" xlink:title="SignificantInvestmentsInSubsidiariesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SignificantInvestmentsInSubsidiariesAxis" xlink:to="SignificantInvestmentsInSubsidiariesDomain" xlink:title="definition: SignificantInvestmentsInSubsidiariesAxis to SignificantInvestmentsInSubsidiariesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SignificantInvestmentsInSubsidiariesDomain" xlink:label="SignificantInvestmentsInSubsidiariesDomain_2" xlink:title="SignificantInvestmentsInSubsidiariesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SignificantInvestmentsInSubsidiariesAxis" xlink:to="SignificantInvestmentsInSubsidiariesDomain_2" xlink:title="definition: SignificantInvestmentsInSubsidiariesAxis to SignificantInvestmentsInSubsidiariesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixPharmaceuticalsLtdMember" xlink:label="TelixPharmaceuticalsLtdMember" xlink:title="TelixPharmaceuticalsLtdMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixPharmaceuticalsLtdMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixPharmaceuticalsLtdMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixPharmaceuticalsInnovationsMember" xlink:label="TelixPharmaceuticalsInnovationsMember" xlink:title="TelixPharmaceuticalsInnovationsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixPharmaceuticalsInnovationsMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixPharmaceuticalsInnovationsMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixPharmaceuticalsHoldingsPtyLimitedMember" xlink:label="TelixPharmaceuticalsHoldingsPtyLimitedMember" xlink:title="TelixPharmaceuticalsHoldingsPtyLimitedMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixPharmaceuticalsHoldingsPtyLimitedMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixPharmaceuticalsHoldingsPtyLimitedMember" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixPharmaceuticalsInternationalHoldingsPtyLimitedMember" xlink:label="TelixPharmaceuticalsInternationalHoldingsPtyLimitedMember" xlink:title="TelixPharmaceuticalsInternationalHoldingsPtyLimitedMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixPharmaceuticalsInternationalHoldingsPtyLimitedMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixPharmaceuticalsInternationalHoldingsPtyLimitedMember" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixPharmaceuticalsAustraliaHoldingsPtyLimitedMember" xlink:label="TelixPharmaceuticalsAustraliaHoldingsPtyLimitedMember" xlink:title="TelixPharmaceuticalsAustraliaHoldingsPtyLimitedMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixPharmaceuticalsAustraliaHoldingsPtyLimitedMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixPharmaceuticalsAustraliaHoldingsPtyLimitedMember" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixPharmaceuticalsANZPtyLtdMember" xlink:label="TelixPharmaceuticalsANZPtyLtdMember" xlink:title="TelixPharmaceuticalsANZPtyLtdMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixPharmaceuticalsANZPtyLtdMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixPharmaceuticalsANZPtyLtdMember" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixPharmaceuticalsCorporatePtyLimitedMember" xlink:label="TelixPharmaceuticalsCorporatePtyLimitedMember" xlink:title="TelixPharmaceuticalsCorporatePtyLimitedMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixPharmaceuticalsCorporatePtyLimitedMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixPharmaceuticalsCorporatePtyLimitedMember" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixPharmaceuticalsBelgiumSRLMember" xlink:label="TelixPharmaceuticalsBelgiumSRLMember" xlink:title="TelixPharmaceuticalsBelgiumSRLMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixPharmaceuticalsBelgiumSRLMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixPharmaceuticalsBelgiumSRLMember" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixInnovationsSAMember" xlink:label="TelixInnovationsSAMember" xlink:title="TelixInnovationsSAMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixInnovationsSAMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixInnovationsSAMember" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixInnovationsRphParticipacoesLtdMember" xlink:label="TelixInnovationsRphParticipacoesLtdMember" xlink:title="TelixInnovationsRphParticipacoesLtdMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixInnovationsRphParticipacoesLtdMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixInnovationsRphParticipacoesLtdMember" order="10.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixPharmaceuticalsCanadaIncMember" xlink:label="TelixPharmaceuticalsCanadaIncMember" xlink:title="TelixPharmaceuticalsCanadaIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixPharmaceuticalsCanadaIncMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixPharmaceuticalsCanadaIncMember" order="11.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixARTMSIncMember" xlink:label="TelixARTMSIncMember" xlink:title="TelixARTMSIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixARTMSIncMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixARTMSIncMember" order="12.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixPharmaceuticalsFranceSASMember" xlink:label="TelixPharmaceuticalsFranceSASMember" xlink:title="TelixPharmaceuticalsFranceSASMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixPharmaceuticalsFranceSASMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixPharmaceuticalsFranceSASMember" order="13.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixPharmaceuticalsGermanyGmbHMember" xlink:label="TelixPharmaceuticalsGermanyGmbHMember" xlink:title="TelixPharmaceuticalsGermanyGmbHMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixPharmaceuticalsGermanyGmbHMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixPharmaceuticalsGermanyGmbHMember" order="14.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_RhinePharmaGmbHFormerlyTelixPharmaceuticalsGermanyGmbHMember" xlink:label="RhinePharmaGmbHFormerlyTelixPharmaceuticalsGermanyGmbHMember" xlink:title="RhinePharmaGmbHFormerlyTelixPharmaceuticalsGermanyGmbHMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="RhinePharmaGmbHFormerlyTelixPharmaceuticalsGermanyGmbHMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to RhinePharmaGmbHFormerlyTelixPharmaceuticalsGermanyGmbHMember" order="15.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TherapeiaGmbHCoKGMember" xlink:label="TherapeiaGmbHCoKGMember" xlink:title="TherapeiaGmbHCoKGMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TherapeiaGmbHCoKGMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TherapeiaGmbHCoKGMember" order="16.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TherapeiaVerwaltungsGmbHMember" xlink:label="TherapeiaVerwaltungsGmbHMember" xlink:title="TherapeiaVerwaltungsGmbHMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TherapeiaVerwaltungsGmbHMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TherapeiaVerwaltungsGmbHMember" order="17.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DedicaidGmbHMember" xlink:label="DedicaidGmbHMember" xlink:title="DedicaidGmbHMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="DedicaidGmbHMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to DedicaidGmbHMember" order="18.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixPharmaJapanKKMember" xlink:label="TelixPharmaJapanKKMember" xlink:title="TelixPharmaJapanKKMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixPharmaJapanKKMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixPharmaJapanKKMember" order="19.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixPharmaceuticalsNZLimitedMember" xlink:label="TelixPharmaceuticalsNZLimitedMember" xlink:title="TelixPharmaceuticalsNZLimitedMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixPharmaceuticalsNZLimitedMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixPharmaceuticalsNZLimitedMember" order="20.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixPharmaceuticalsSingaporePteLtdMember" xlink:label="TelixPharmaceuticalsSingaporePteLtdMember" xlink:title="TelixPharmaceuticalsSingaporePteLtdMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixPharmaceuticalsSingaporePteLtdMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixPharmaceuticalsSingaporePteLtdMember" order="21.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixPharmaceuticalsSwitzerlandGmbHMember" xlink:label="TelixPharmaceuticalsSwitzerlandGmbHMember" xlink:title="TelixPharmaceuticalsSwitzerlandGmbHMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixPharmaceuticalsSwitzerlandGmbHMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixPharmaceuticalsSwitzerlandGmbHMember" order="22.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixPharmaceuticalsUKLtdFormerlyTelixLifeSciencesUKLtdMember" xlink:label="TelixPharmaceuticalsUKLtdFormerlyTelixLifeSciencesUKLtdMember" xlink:title="TelixPharmaceuticalsUKLtdFormerlyTelixLifeSciencesUKLtdMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixPharmaceuticalsUKLtdFormerlyTelixLifeSciencesUKLtdMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixPharmaceuticalsUKLtdFormerlyTelixLifeSciencesUKLtdMember" order="23.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_LightpointSurgicalLtdMember" xlink:label="LightpointSurgicalLtdMember" xlink:title="LightpointSurgicalLtdMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="LightpointSurgicalLtdMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to LightpointSurgicalLtdMember" order="24.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_LightpointSurgicalSpainSLMember" xlink:label="LightpointSurgicalSpainSLMember" xlink:title="LightpointSurgicalSpainSLMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="LightpointSurgicalSpainSLMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to LightpointSurgicalSpainSLMember" order="25.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixPharmaceuticalsUSIncMember" xlink:label="TelixPharmaceuticalsUSIncMember" xlink:title="TelixPharmaceuticalsUSIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixPharmaceuticalsUSIncMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixPharmaceuticalsUSIncMember" order="26.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixOptimalTracersLLCMember" xlink:label="TelixOptimalTracersLLCMember" xlink:title="TelixOptimalTracersLLCMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixOptimalTracersLLCMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixOptimalTracersLLCMember" order="27.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixIsoTherapeuticsGroupIncMember" xlink:label="TelixIsoTherapeuticsGroupIncMember" xlink:title="TelixIsoTherapeuticsGroupIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixIsoTherapeuticsGroupIncMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixIsoTherapeuticsGroupIncMember" order="28.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_TelixQSAMIncMember" xlink:label="TelixQSAMIncMember" xlink:title="TelixQSAMIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="TelixQSAMIncMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to TelixQSAMIncMember" order="29.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_QSAMTherapeuticsIncMember" xlink:label="QSAMTherapeuticsIncMember" xlink:title="QSAMTherapeuticsIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="QSAMTherapeuticsIncMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to QSAMTherapeuticsIncMember" order="30.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ARTMSUSIncMember" xlink:label="ARTMSUSIncMember" xlink:title="ARTMSUSIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SignificantInvestmentsInSubsidiariesDomain" xlink:to="ARTMSUSIncMember" xlink:title="definition: SignificantInvestmentsInSubsidiariesDomain to ARTMSUSIncMember" order="31.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/RemunerationOfAuditorDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" xlink:label="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" xlink:title="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AuditorsRemunerationDisclosureAbstract" xlink:label="AuditorsRemunerationDisclosureAbstract" xlink:title="AuditorsRemunerationDisclosureAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" xlink:to="AuditorsRemunerationDisclosureAbstract" xlink:title="definition: DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems to AuditorsRemunerationDisclosureAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AuditorsRemunerationForAuditServices" xlink:label="AuditorsRemunerationForAuditServices" xlink:title="AuditorsRemunerationForAuditServices" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" xlink:to="AuditorsRemunerationForAuditServices" xlink:title="definition: DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems to AuditorsRemunerationForAuditServices" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AuditorsRemunerationForTaxServices" xlink:label="AuditorsRemunerationForTaxServices" xlink:title="AuditorsRemunerationForTaxServices" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" xlink:to="AuditorsRemunerationForTaxServices" xlink:title="definition: DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems to AuditorsRemunerationForTaxServices" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AuditorsRemunerationForOtherServices" xlink:label="AuditorsRemunerationForOtherServices" xlink:title="AuditorsRemunerationForOtherServices" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" xlink:to="AuditorsRemunerationForOtherServices" xlink:title="definition: DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems to AuditorsRemunerationForOtherServices" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AuditorsRemuneration" xlink:label="AuditorsRemuneration" xlink:title="AuditorsRemuneration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" xlink:to="AuditorsRemuneration" xlink:title="definition: DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems to AuditorsRemuneration" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesTable" xlink:label="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesTable" xlink:title="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems" xlink:to="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesTable" xlink:title="definition: DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesLineItems to DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesTable" order="6.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SeparateManagementEntitiesAxis" xlink:label="SeparateManagementEntitiesAxis" xlink:title="SeparateManagementEntitiesAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesTable" xlink:to="SeparateManagementEntitiesAxis" xlink:title="definition: DisclosureOfAmountsIncurredByEntityForProvisionOfKeyManagementPersonnelServicesProvidedBySeparateManagementEntitiesTable to SeparateManagementEntitiesAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SeparateManagementEntitiesDomain" xlink:label="SeparateManagementEntitiesDomain" xlink:title="SeparateManagementEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="SeparateManagementEntitiesAxis" xlink:to="SeparateManagementEntitiesDomain" xlink:title="definition: SeparateManagementEntitiesAxis to SeparateManagementEntitiesDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_SeparateManagementEntitiesDomain" xlink:label="SeparateManagementEntitiesDomain_2" xlink:title="SeparateManagementEntitiesDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="SeparateManagementEntitiesAxis" xlink:to="SeparateManagementEntitiesDomain_2" xlink:title="definition: SeparateManagementEntitiesAxis to SeparateManagementEntitiesDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PricewaterhouseCoopersAustraliaAndRelatedNetworkFirmsMember" xlink:label="PricewaterhouseCoopersAustraliaAndRelatedNetworkFirmsMember" xlink:title="PricewaterhouseCoopersAustraliaAndRelatedNetworkFirmsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SeparateManagementEntitiesDomain" xlink:to="PricewaterhouseCoopersAustraliaAndRelatedNetworkFirmsMember" xlink:title="definition: SeparateManagementEntitiesDomain to PricewaterhouseCoopersAustraliaAndRelatedNetworkFirmsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_OtherAuditorsAndTheirRelatedNetworkFirmsMember" xlink:label="OtherAuditorsAndTheirRelatedNetworkFirmsMember" xlink:title="OtherAuditorsAndTheirRelatedNetworkFirmsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="SeparateManagementEntitiesDomain" xlink:to="OtherAuditorsAndTheirRelatedNetworkFirmsMember" xlink:title="definition: SeparateManagementEntitiesDomain to OtherAuditorsAndTheirRelatedNetworkFirmsMember" order="2.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EventsOccurringAfterReportingPeriodAcquisitionOfRlsUsaIncDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:label="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:title="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" xlink:label="AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" xlink:title="AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_MeasurementPeriod" xlink:label="MeasurementPeriod" xlink:title="MeasurementPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="MeasurementPeriod" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to MeasurementPeriod" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashTransferred" xlink:label="CashTransferred" xlink:title="CashTransferred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="CashTransferred" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to CashTransferred" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesIncurred" xlink:label="LiabilitiesIncurred" xlink:title="LiabilitiesIncurred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="LiabilitiesIncurred" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to LiabilitiesIncurred" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_EstimatedAmountsOfIdentifiableAssetsAndAcquiredLiabilitiesAssumed" xlink:label="EstimatedAmountsOfIdentifiableAssetsAndAcquiredLiabilitiesAssumed" xlink:title="EstimatedAmountsOfIdentifiableAssetsAndAcquiredLiabilitiesAssumed" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="EstimatedAmountsOfIdentifiableAssetsAndAcquiredLiabilitiesAssumed" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to EstimatedAmountsOfIdentifiableAssetsAndAcquiredLiabilitiesAssumed" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_IdentifiableAssetsAcquiredLiabilitiesAssumed" xlink:label="IdentifiableAssetsAcquiredLiabilitiesAssumed" xlink:title="IdentifiableAssetsAcquiredLiabilitiesAssumed" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="IdentifiableAssetsAcquiredLiabilitiesAssumed" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to IdentifiableAssetsAcquiredLiabilitiesAssumed" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_GoodwillAndIntangibleAssetsRecognisedAsOfAcquisitionDate" xlink:label="GoodwillAndIntangibleAssetsRecognisedAsOfAcquisitionDate" xlink:title="GoodwillAndIntangibleAssetsRecognisedAsOfAcquisitionDate" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="GoodwillAndIntangibleAssetsRecognisedAsOfAcquisitionDate" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to GoodwillAndIntangibleAssetsRecognisedAsOfAcquisitionDate" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AcquisitiondateFairValueOfTotalConsiderationTransferred" xlink:label="AcquisitiondateFairValueOfTotalConsiderationTransferred" xlink:title="AcquisitiondateFairValueOfTotalConsiderationTransferred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="AcquisitiondateFairValueOfTotalConsiderationTransferred" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to AcquisitiondateFairValueOfTotalConsiderationTransferred" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:label="DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:title="DisclosureOfNonadjustingEventsAfterReportingPeriodTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to DisclosureOfNonadjustingEventsAfterReportingPeriodTable" order="9.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NonadjustingEventsAfterReportingPeriodAxis" xlink:label="NonadjustingEventsAfterReportingPeriodAxis" xlink:title="NonadjustingEventsAfterReportingPeriodAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:to="NonadjustingEventsAfterReportingPeriodAxis" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodTable to NonadjustingEventsAfterReportingPeriodAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" xlink:label="NonadjustingEventsAfterReportingPeriodDomain" xlink:title="NonadjustingEventsAfterReportingPeriodDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="NonadjustingEventsAfterReportingPeriodAxis" xlink:to="NonadjustingEventsAfterReportingPeriodDomain" xlink:title="definition: NonadjustingEventsAfterReportingPeriodAxis to NonadjustingEventsAfterReportingPeriodDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" xlink:label="NonadjustingEventsAfterReportingPeriodDomain_2" xlink:title="NonadjustingEventsAfterReportingPeriodDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="NonadjustingEventsAfterReportingPeriodAxis" xlink:to="NonadjustingEventsAfterReportingPeriodDomain_2" xlink:title="definition: NonadjustingEventsAfterReportingPeriodAxis to NonadjustingEventsAfterReportingPeriodDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_SubsequentEventsMember" xlink:label="SubsequentEventsMember" xlink:title="SubsequentEventsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NonadjustingEventsAfterReportingPeriodDomain" xlink:to="SubsequentEventsMember" xlink:title="definition: NonadjustingEventsAfterReportingPeriodDomain to SubsequentEventsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsAxis" xlink:label="BusinessCombinationsAxis" xlink:title="BusinessCombinationsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:to="BusinessCombinationsAxis" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodTable to BusinessCombinationsAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain_2" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain_2" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_RLSUSAIncMember" xlink:label="RLSUSAIncMember" xlink:title="RLSUSAIncMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="RLSUSAIncMember" xlink:title="definition: BusinessCombinationsDomain to RLSUSAIncMember" order="1.0" />
  </link:definitionLink>
  <link:definitionLink xlink:type="extended" xlink:role="http://telixpharma.com/role/EventsOccurringAfterReportingPeriodAcquisitionOfAssetsDetails">
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:label="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:title="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" xlink:label="AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" xlink:title="AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to AcquisitiondateFairValueOfTotalConsiderationTransferredAbstract" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_AcquisitiondateFairValueOfFinalPurchasePriceConsideration" xlink:label="AcquisitiondateFairValueOfFinalPurchasePriceConsideration" xlink:title="AcquisitiondateFairValueOfFinalPurchasePriceConsideration" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="AcquisitiondateFairValueOfFinalPurchasePriceConsideration" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to AcquisitiondateFairValueOfFinalPurchasePriceConsideration" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_CashTransferred" xlink:label="CashTransferred" xlink:title="CashTransferred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="CashTransferred" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to CashTransferred" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_EquityInterestsOfAcquirer" xlink:label="EquityInterestsOfAcquirer" xlink:title="EquityInterestsOfAcquirer" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="EquityInterestsOfAcquirer" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to EquityInterestsOfAcquirer" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_DeferredPaymentInEquity" xlink:label="DeferredPaymentInEquity" xlink:title="DeferredPaymentInEquity" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="DeferredPaymentInEquity" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to DeferredPaymentInEquity" order="5.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_IndemnityPeriod" xlink:label="IndemnityPeriod" xlink:title="IndemnityPeriod" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="IndemnityPeriod" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to IndemnityPeriod" order="6.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_LiabilitiesIncurred" xlink:label="LiabilitiesIncurred" xlink:title="LiabilitiesIncurred" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="LiabilitiesIncurred" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to LiabilitiesIncurred" order="7.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_NumberOfProductsToBeDevelopedForRoyaltiesAndSublicenseFeesPayment" xlink:label="NumberOfProductsToBeDevelopedForRoyaltiesAndSublicenseFeesPayment" xlink:title="NumberOfProductsToBeDevelopedForRoyaltiesAndSublicenseFeesPayment" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="NumberOfProductsToBeDevelopedForRoyaltiesAndSublicenseFeesPayment" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to NumberOfProductsToBeDevelopedForRoyaltiesAndSublicenseFeesPayment" order="8.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_PercentageOfOwnershipInterest" xlink:label="PercentageOfOwnershipInterest" xlink:title="PercentageOfOwnershipInterest" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="PercentageOfOwnershipInterest" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to PercentageOfOwnershipInterest" order="9.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:label="DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:title="DisclosureOfNonadjustingEventsAfterReportingPeriodTable" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems" xlink:to="DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodLineItems to DisclosureOfNonadjustingEventsAfterReportingPeriodTable" order="10.0" t1:closed="true" t1:contextElement="segment" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NonadjustingEventsAfterReportingPeriodAxis" xlink:label="NonadjustingEventsAfterReportingPeriodAxis" xlink:title="NonadjustingEventsAfterReportingPeriodAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:to="NonadjustingEventsAfterReportingPeriodAxis" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodTable to NonadjustingEventsAfterReportingPeriodAxis" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" xlink:label="NonadjustingEventsAfterReportingPeriodDomain" xlink:title="NonadjustingEventsAfterReportingPeriodDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="NonadjustingEventsAfterReportingPeriodAxis" xlink:to="NonadjustingEventsAfterReportingPeriodDomain" xlink:title="definition: NonadjustingEventsAfterReportingPeriodAxis to NonadjustingEventsAfterReportingPeriodDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_NonadjustingEventsAfterReportingPeriodDomain" xlink:label="NonadjustingEventsAfterReportingPeriodDomain_2" xlink:title="NonadjustingEventsAfterReportingPeriodDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="NonadjustingEventsAfterReportingPeriodAxis" xlink:to="NonadjustingEventsAfterReportingPeriodDomain_2" xlink:title="definition: NonadjustingEventsAfterReportingPeriodAxis to NonadjustingEventsAfterReportingPeriodDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_SubsequentEventsMember" xlink:label="SubsequentEventsMember" xlink:title="SubsequentEventsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="NonadjustingEventsAfterReportingPeriodDomain" xlink:to="SubsequentEventsMember" xlink:title="definition: NonadjustingEventsAfterReportingPeriodDomain to SubsequentEventsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsAxis" xlink:label="BusinessCombinationsAxis" xlink:title="BusinessCombinationsAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:to="BusinessCombinationsAxis" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodTable to BusinessCombinationsAxis" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BusinessCombinationsDomain" xlink:label="BusinessCombinationsDomain_2" xlink:title="BusinessCombinationsDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="BusinessCombinationsAxis" xlink:to="BusinessCombinationsDomain_2" xlink:title="definition: BusinessCombinationsAxis to BusinessCombinationsDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_NextGenerationTherapeuticAssetsMember" xlink:label="NextGenerationTherapeuticAssetsMember" xlink:title="NextGenerationTherapeuticAssetsMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="BusinessCombinationsDomain" xlink:to="NextGenerationTherapeuticAssetsMember" xlink:title="definition: BusinessCombinationsDomain to NextGenerationTherapeuticAssetsMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeAxis" xlink:label="RangeAxis" xlink:title="RangeAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:to="RangeAxis" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodTable to RangeAxis" order="3.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="RangeDomain" xlink:title="RangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="RangeAxis" xlink:to="RangeDomain" xlink:title="definition: RangeAxis to RangeDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_RangeDomain" xlink:label="RangeDomain_2" xlink:title="RangeDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="RangeAxis" xlink:to="RangeDomain_2" xlink:title="definition: RangeAxis to RangeDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_BottomOfRangeMember" xlink:label="BottomOfRangeMember" xlink:title="BottomOfRangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeDomain" xlink:to="BottomOfRangeMember" xlink:title="definition: RangeDomain to BottomOfRangeMember" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.ifrs.org/taxonomy/2024-03-27/full_ifrs/full_ifrs-cor_2024-03-27.xsd#ifrs-full_TopOfRangeMember" xlink:label="TopOfRangeMember" xlink:title="TopOfRangeMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="RangeDomain" xlink:to="TopOfRangeMember" xlink:title="definition: RangeDomain to TopOfRangeMember" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_TitleOfIndividualAxis" xlink:label="TitleOfIndividualAxis" xlink:title="TitleOfIndividualAxis" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="DisclosureOfNonadjustingEventsAfterReportingPeriodTable" xlink:to="TitleOfIndividualAxis" xlink:title="definition: DisclosureOfNonadjustingEventsAfterReportingPeriodTable to TitleOfIndividualAxis" order="4.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="TitleOfIndividualWithRelationshipToEntityDomain" xlink:title="TitleOfIndividualWithRelationshipToEntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="TitleOfIndividualAxis" xlink:to="TitleOfIndividualWithRelationshipToEntityDomain" xlink:title="definition: TitleOfIndividualAxis to TitleOfIndividualWithRelationshipToEntityDomain" order="1.0" />
    <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2024/elts/srt-2024.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="TitleOfIndividualWithRelationshipToEntityDomain_2" xlink:title="TitleOfIndividualWithRelationshipToEntityDomain" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="TitleOfIndividualAxis" xlink:to="TitleOfIndividualWithRelationshipToEntityDomain_2" xlink:title="definition: TitleOfIndividualAxis to TitleOfIndividualWithRelationshipToEntityDomain_2" order="2.0" />
    <link:loc xlink:type="locator" xlink:href="tlx-20241231.xsd#tlx_ManagingDirectorAndGroupChiefExecutiveOfficerMember" xlink:label="ManagingDirectorAndGroupChiefExecutiveOfficerMember" xlink:title="ManagingDirectorAndGroupChiefExecutiveOfficerMember" />
    <link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="TitleOfIndividualWithRelationshipToEntityDomain" xlink:to="ManagingDirectorAndGroupChiefExecutiveOfficerMember" xlink:title="definition: TitleOfIndividualWithRelationshipToEntityDomain to ManagingDirectorAndGroupChiefExecutiveOfficerMember" order="1.0" />
  </link:definitionLink>
</link:linkbase>
