<?xml version="1.0" encoding="utf-8"?>
<!--Generated by DataTracks Rainbow version 3.0 for Toppan Merrill on 21-March-2022 [06:11:32] {PM}-->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:xbrldt="http://xbrl.org/2005/xbrldt">
<roleRef xlink:type="simple" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#ConsolidatedStatementsOfChangesInEquity" roleURI="http://www.argenx.com/role/ConsolidatedStatementsOfChangesInEquity" />
<roleRef xlink:type="simple" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#CoverPage" roleURI="http://www.argenx.com/role/CoverPage" />
<roleRef xlink:type="simple" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#ConsolidatedStatementsOfProfitAndLoss" roleURI="http://www.argenx.com/role/ConsolidatedStatementsOfProfitAndLoss" />
<roleRef xlink:type="simple" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#ConsolidatedStatementsOfCashFlows" roleURI="http://www.argenx.com/role/ConsolidatedStatementsOfCashFlows" />
<roleRef xlink:type="simple" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#ConsolidatedStatementsOfFinancialPosition" roleURI="http://www.argenx.com/role/ConsolidatedStatementsOfFinancialPosition" />
<roleRef xlink:type="simple" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#ConsolidatedStatementsOfComprehensiveIncomeAndLoss" roleURI="http://www.argenx.com/role/ConsolidatedStatementsOfComprehensiveIncomeAndLoss" />
<roleRef xlink:type="simple" xlink:href="http://www.esma.europa.eu/taxonomy/2020-03-16/esef_cor.xsd#ifrs-dim_role-990000" roleURI="http://www.esma.europa.eu/xbrl/role/cor/ifrs-dim_role-990000" />
<roleRef xlink:type="simple" xlink:href="http://www.esma.europa.eu/taxonomy/2020-03-16/esef_cor.xsd#esef_role-999999" roleURI="http://www.esma.europa.eu/xbrl/role/cor/esef_role-999999" />
<roleRef xlink:type="simple" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#Anchoring" roleURI="http://www.argenx.com/role/Anchoring" />
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" />
<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" />
<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" />
<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" />
<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" />
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/notAll" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#notAll" />
<arcroleRef arcroleURI="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/arcrole/esma-arcrole-2018-11-21.xsd#wider-narrower" />
<definitionLink xlink:type="extended" xlink:role="http://www.argenx.com/role/ConsolidatedStatementsOfChangesInEquity">
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_StatementOfChangesInEquityLineItems" xlink:label="loc_ifrs-full_StatementOfChangesInEquityLineItems_122" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_Equity" xlink:label="loc_ifrs-full_Equity_130" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_StatementOfChangesInEquityLineItems_122" xlink:to="loc_ifrs-full_Equity_130" use="optional" order="1" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherComprehensiveIncome" xlink:label="loc_ifrs-full_OtherComprehensiveIncome_717847" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_StatementOfChangesInEquityLineItems_122" xlink:to="loc_ifrs-full_OtherComprehensiveIncome_717847" use="optional" order="2" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IncreaseDecreaseThroughExerciseOfOptions" xlink:label="loc_ifrs-full_IncreaseDecreaseThroughExerciseOfOptions_137" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_StatementOfChangesInEquityLineItems_122" xlink:to="loc_ifrs-full_IncreaseDecreaseThroughExerciseOfOptions_137" use="optional" order="3" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_StatementOfChangesInEquityTable" xlink:label="loc_ifrs-full_StatementOfChangesInEquityTable_117" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_ifrs-full_StatementOfChangesInEquityLineItems_122" xlink:to="loc_ifrs-full_StatementOfChangesInEquityTable_117" xbrldt:contextElement="scenario" xbrldt:closed="true" use="optional" order="4" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ComponentsOfEquityAxis" xlink:label="loc_ifrs-full_ComponentsOfEquityAxis_118" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_ifrs-full_StatementOfChangesInEquityTable_117" xlink:to="loc_ifrs-full_ComponentsOfEquityAxis_118" use="optional" order="5" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_EquityMember" xlink:label="loc_ifrs-full_EquityMember_119" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_ifrs-full_ComponentsOfEquityAxis_118" xlink:to="loc_ifrs-full_EquityMember_119" use="optional" order="6" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_EquityAttributableToOwnersOfParentMember" xlink:label="loc_ifrs-full_EquityAttributableToOwnersOfParentMember_127" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_EquityMember_119" xlink:to="loc_ifrs-full_EquityAttributableToOwnersOfParentMember_127" use="optional" order="7" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IssuedCapitalMember" xlink:label="loc_ifrs-full_IssuedCapitalMember_123" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_EquityMember_119" xlink:to="loc_ifrs-full_IssuedCapitalMember_123" use="optional" order="8" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_SharePremiumMember" xlink:label="loc_ifrs-full_SharePremiumMember_124" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_EquityMember_119" xlink:to="loc_ifrs-full_SharePremiumMember_124" use="optional" order="9" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ReserveOfExchangeDifferencesOnTranslationMember" xlink:label="loc_ifrs-full_ReserveOfExchangeDifferencesOnTranslationMember_717846" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_EquityMember_119" xlink:to="loc_ifrs-full_ReserveOfExchangeDifferencesOnTranslationMember_717846" use="optional" order="10" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherReservesMember" xlink:label="loc_ifrs-full_OtherReservesMember_718825" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_EquityMember_119" xlink:to="loc_ifrs-full_OtherReservesMember_718825" use="optional" order="11" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_OtherReservesExcludingExchangeDifferencesOnTranslationMember" xlink:label="loc_argx_OtherReservesExcludingExchangeDifferencesOnTranslationMember_126" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_OtherReservesMember_718825" xlink:to="loc_argx_OtherReservesExcludingExchangeDifferencesOnTranslationMember_126" use="optional" order="12" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ReserveOfSharebasedPaymentsMember" xlink:label="loc_ifrs-full_ReserveOfSharebasedPaymentsMember_718826" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_argx_OtherReservesExcludingExchangeDifferencesOnTranslationMember_126" xlink:to="loc_ifrs-full_ReserveOfSharebasedPaymentsMember_718826" use="optional" order="13" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_RetainedEarningsMember" xlink:label="loc_ifrs-full_RetainedEarningsMember_125" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_EquityMember_119" xlink:to="loc_ifrs-full_RetainedEarningsMember_125" use="optional" order="14" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ComprehensiveIncome" xlink:label="loc_ifrs-full_ComprehensiveIncome_717848" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_StatementOfChangesInEquityLineItems_122" xlink:to="loc_ifrs-full_ComprehensiveIncome_717848" use="optional" order="15" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ProfitLoss" xlink:label="loc_ifrs-full_ProfitLoss_131" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_StatementOfChangesInEquityLineItems_122" xlink:to="loc_ifrs-full_ProfitLoss_131" use="optional" order="16" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IncreaseDecreaseThroughSharebasedPaymentTransactions" xlink:label="loc_ifrs-full_IncreaseDecreaseThroughSharebasedPaymentTransactions_132" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_StatementOfChangesInEquityLineItems_122" xlink:to="loc_ifrs-full_IncreaseDecreaseThroughSharebasedPaymentTransactions_132" use="optional" order="17" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_AccountingTreatmentOfTheShareSubscriptionAgreement" xlink:label="loc_argx_AccountingTreatmentOfTheShareSubscriptionAgreement_136" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_StatementOfChangesInEquityLineItems_122" xlink:to="loc_argx_AccountingTreatmentOfTheShareSubscriptionAgreement_136" use="optional" order="18" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_DecreaseIncreaseThroughTaxOnSharebasedPaymentTransactions" xlink:label="loc_ifrs-full_DecreaseIncreaseThroughTaxOnSharebasedPaymentTransactions_685469" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_StatementOfChangesInEquityLineItems_122" xlink:to="loc_ifrs-full_DecreaseIncreaseThroughTaxOnSharebasedPaymentTransactions_685469" use="optional" order="19" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IssueOfEquity" xlink:label="loc_ifrs-full_IssueOfEquity_133" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_StatementOfChangesInEquityLineItems_122" xlink:to="loc_ifrs-full_IssueOfEquity_133" use="optional" order="20" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ShareIssueRelatedCost" xlink:label="loc_ifrs-full_ShareIssueRelatedCost_135" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_StatementOfChangesInEquityLineItems_122" xlink:to="loc_ifrs-full_ShareIssueRelatedCost_135" use="optional" order="21" />
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.esma.europa.eu/xbrl/role/cor/ifrs-dim_role-990000" />
<definitionLink xlink:type="extended" xlink:role="http://www.esma.europa.eu/xbrl/role/cor/esef_role-999999">
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_AdjustmentsForFairValueGainsLosses" xlink:label="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" />
<loc xlink:type="locator" xlink:href="http://www.esma.europa.eu/taxonomy/2020-03-16/esef_cor.xsd#esef_cor_LineItemsNotDimensionallyQualified" xlink:label="loc_LineItemsNotDimensionallyQualified" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_LineItemsNotDimensionallyQualified" xbrldt:contextElement="scenario" xbrldt:closed="true" use="optional" order="1" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_AdjustmentsForSharebasedPayments" xlink:label="loc_ifrs-full_AdjustmentsForSharebasedPayments_87" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_AdjustmentsForSharebasedPayments_87" use="optional" order="2" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_AdjustmentsForProvisions" xlink:label="loc_ifrs-full_AdjustmentsForProvisions_86" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_AdjustmentsForProvisions_86" use="optional" order="3" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_AdjustmentsForDepreciationExpense" xlink:label="loc_ifrs-full_AdjustmentsForDepreciationExpense_84" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_AdjustmentsForDepreciationExpense_84" use="optional" order="4" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_AdjustmentsForAmortisationExpense" xlink:label="loc_ifrs-full_AdjustmentsForAmortisationExpense_83" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_AdjustmentsForAmortisationExpense_83" use="optional" order="5" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IncreaseDecreaseInCashAndCashEquivalentsBeforeEffectOfExchangeRateChanges" xlink:label="loc_ifrs-full_IncreaseDecreaseInCashAndCashEquivalentsBeforeEffectOfExchangeRateChanges_111" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_IncreaseDecreaseInCashAndCashEquivalentsBeforeEffectOfExchangeRateChanges_111" use="optional" order="6" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_AdjustmentsForIncreaseDecreaseInTradeAndOtherPayables" xlink:label="loc_ifrs-full_AdjustmentsForIncreaseDecreaseInTradeAndOtherPayables_92" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_AdjustmentsForIncreaseDecreaseInTradeAndOtherPayables_92" use="optional" order="7" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_AdjustmentsForDecreaseIncreaseInOtherCurrentAssets" xlink:label="loc_ifrs-full_AdjustmentsForDecreaseIncreaseInOtherCurrentAssets_91" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_AdjustmentsForDecreaseIncreaseInOtherCurrentAssets_91" use="optional" order="8" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_AdjustmentsForDecreaseIncreaseInTradeAndOtherReceivables" xlink:label="loc_ifrs-full_AdjustmentsForDecreaseIncreaseInTradeAndOtherReceivables_90" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_AdjustmentsForDecreaseIncreaseInTradeAndOtherReceivables_90" use="optional" order="9" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_PaymentsForShareIssueCosts" xlink:label="loc_ifrs-full_PaymentsForShareIssueCosts_107" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_PaymentsForShareIssueCosts_107" use="optional" order="10" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ProceedsFromIssuingShares" xlink:label="loc_ifrs-full_ProceedsFromIssuingShares_106" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_ProceedsFromIssuingShares_106" use="optional" order="11" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CashFlowsFromUsedInOperations" xlink:label="loc_ifrs-full_CashFlowsFromUsedInOperations_96" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_CashFlowsFromUsedInOperations_96" use="optional" order="12" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_PaymentsOfLeaseLiabilitiesClassifiedAsFinancingActivities" xlink:label="loc_ifrs-full_PaymentsOfLeaseLiabilitiesClassifiedAsFinancingActivities_105" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_PaymentsOfLeaseLiabilitiesClassifiedAsFinancingActivities_105" use="optional" order="13" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital" xlink:label="loc_ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital_89" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_CashFlowsFromUsedInOperationsBeforeChangesInWorkingCapital_89" use="optional" order="14" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_EffectOfExchangeRateChangesOnCashAndCashEquivalents" xlink:label="loc_ifrs-full_EffectOfExchangeRateChangesOnCashAndCashEquivalents_113" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_EffectOfExchangeRateChangesOnCashAndCashEquivalents_113" use="optional" order="15" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IncomeTaxesPaidRefundClassifiedAsOperatingActivities" xlink:label="loc_ifrs-full_IncomeTaxesPaidRefundClassifiedAsOperatingActivities_98" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_IncomeTaxesPaidRefundClassifiedAsOperatingActivities_98" use="optional" order="16" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_InterestPaidClassifiedAsOperatingActivities" xlink:label="loc_ifrs-full_InterestPaidClassifiedAsOperatingActivities_97" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_InterestPaidClassifiedAsOperatingActivities_97" use="optional" order="17" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CashFlowsFromUsedInFinancingActivities" xlink:label="loc_ifrs-full_CashFlowsFromUsedInFinancingActivities_110" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_CashFlowsFromUsedInFinancingActivities_110" use="optional" order="18" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_AdjustmentsForIncreaseDecreaseInDeferredRevenueNonCurrent" xlink:label="loc_argx_AdjustmentsForIncreaseDecreaseInDeferredRevenueNonCurrent_95" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_argx_AdjustmentsForIncreaseDecreaseInDeferredRevenueNonCurrent_95" use="optional" order="19" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_AdjustmentsForDecreaseIncreaseInOtherNonCurrentAssets" xlink:label="loc_argx_AdjustmentsForDecreaseIncreaseInOtherNonCurrentAssets_94" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_argx_AdjustmentsForDecreaseIncreaseInOtherNonCurrentAssets_94" use="optional" order="20" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_AdjustmentsForIncreaseDecreaseInDeferredRevenueCurrent" xlink:label="loc_argx_AdjustmentsForIncreaseDecreaseInDeferredRevenueCurrent_93" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_argx_AdjustmentsForIncreaseDecreaseInDeferredRevenueCurrent_93" use="optional" order="21" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherAdjustmentsForNoncashItems" xlink:label="loc_ifrs-full_OtherAdjustmentsForNoncashItems_719073" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_OtherAdjustmentsForNoncashItems_719073" use="optional" order="22" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CashAndCashEquivalents" xlink:label="loc_ifrs-full_CashAndCashEquivalents_114" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_CashAndCashEquivalents_114" use="optional" order="23" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_AdjustmentsForDecreaseIncreaseInInventories" xlink:label="loc_ifrs-full_AdjustmentsForDecreaseIncreaseInInventories_685424" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_AdjustmentsForDecreaseIncreaseInInventories_685424" use="optional" order="24" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IncreaseDecreaseThroughExerciseOfOptions" xlink:label="loc_ifrs-full_IncreaseDecreaseThroughExerciseOfOptions_137" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_IncreaseDecreaseThroughExerciseOfOptions_137" use="optional" order="25" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CashFlowsFromUsedInOperatingActivities" xlink:label="loc_ifrs-full_CashFlowsFromUsedInOperatingActivities_99" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_CashFlowsFromUsedInOperatingActivities_99" use="optional" order="26" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_PurchaseOfIntangibleAssetsClassifiedAsInvestingActivities" xlink:label="loc_ifrs-full_PurchaseOfIntangibleAssetsClassifiedAsInvestingActivities_100" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_PurchaseOfIntangibleAssetsClassifiedAsInvestingActivities_100" use="optional" order="27" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_PurchaseOfPropertyPlantAndEquipmentClassifiedAsInvestingActivities" xlink:label="loc_ifrs-full_PurchaseOfPropertyPlantAndEquipmentClassifiedAsInvestingActivities_101" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_PurchaseOfPropertyPlantAndEquipmentClassifiedAsInvestingActivities_101" use="optional" order="28" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_AdjustmentsForIncreaseDecreaseInFinancialAssetsCurrent" xlink:label="loc_argx_AdjustmentsForIncreaseDecreaseInFinancialAssetsCurrent_102" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_argx_AdjustmentsForIncreaseDecreaseInFinancialAssetsCurrent_102" use="optional" order="29" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_InterestReceivedClassifiedAsInvestingActivities" xlink:label="loc_ifrs-full_InterestReceivedClassifiedAsInvestingActivities_103" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_InterestReceivedClassifiedAsInvestingActivities_103" use="optional" order="30" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CashFlowsFromUsedInInvestingActivities" xlink:label="loc_ifrs-full_CashFlowsFromUsedInInvestingActivities_104" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_CashFlowsFromUsedInInvestingActivities_104" use="optional" order="31" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ProceedsFromExerciseOfOptions" xlink:label="loc_ifrs-full_ProceedsFromExerciseOfOptions_109" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_ProceedsFromExerciseOfOptions_109" use="optional" order="32" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_ExchangeGainFromCurrencyConversionOnProceedsFromIssueOfNewShare" xlink:label="loc_argx_ExchangeGainFromCurrencyConversionOnProceedsFromIssueOfNewShare_108" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_argx_ExchangeGainFromCurrencyConversionOnProceedsFromIssueOfNewShare_108" use="optional" order="33" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ComprehensiveIncome" xlink:label="loc_ifrs-full_ComprehensiveIncome_717848" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_ComprehensiveIncome_717848" use="optional" order="34" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NoncurrentLiabilities" xlink:label="loc_ifrs-full_NoncurrentLiabilities_44" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_NoncurrentLiabilities_44" use="optional" order="35" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_SharePremium" xlink:label="loc_ifrs-full_SharePremium_40" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_SharePremium_40" use="optional" order="36" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ReserveOfExchangeDifferencesOnTranslation" xlink:label="loc_ifrs-full_ReserveOfExchangeDifferencesOnTranslation_717849" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_ReserveOfExchangeDifferencesOnTranslation_717849" use="optional" order="37" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IssuedCapital" xlink:label="loc_ifrs-full_IssuedCapital_39" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_IssuedCapital_39" use="optional" order="38" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CurrentLiabilities" xlink:label="loc_ifrs-full_CurrentLiabilities_48" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_CurrentLiabilities_48" use="optional" order="39" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherNoncurrentAssets" xlink:label="loc_ifrs-full_OtherNoncurrentAssets_33" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_OtherNoncurrentAssets_33" use="optional" order="40" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_Equity" xlink:label="loc_ifrs-full_Equity_43" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_Equity_43" use="optional" order="41" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_ResearchAndDevelopmentIncentiveReceivablesNoncurrent" xlink:label="loc_argx_ResearchAndDevelopmentIncentiveReceivablesNoncurrent_32" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_argx_ResearchAndDevelopmentIncentiveReceivablesNoncurrent_32" use="optional" order="42" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CurrentAssets" xlink:label="loc_ifrs-full_CurrentAssets_30" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_CurrentAssets_30" use="optional" order="43" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_RetainedEarnings" xlink:label="loc_ifrs-full_RetainedEarnings_41" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_RetainedEarnings_41" use="optional" order="44" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_Liabilities" xlink:label="loc_ifrs-full_Liabilities_53" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_Liabilities_53" use="optional" order="45" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_DeferredIncomeClassifiedAsNoncurrent" xlink:label="loc_ifrs-full_DeferredIncomeClassifiedAsNoncurrent_47" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_DeferredIncomeClassifiedAsNoncurrent_47" use="optional" order="46" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_PropertyPlantAndEquipment" xlink:label="loc_ifrs-full_PropertyPlantAndEquipment_35" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_PropertyPlantAndEquipment_35" use="optional" order="47" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IntangibleAssetsOtherThanGoodwill" xlink:label="loc_ifrs-full_IntangibleAssetsOtherThanGoodwill_36" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_IntangibleAssetsOtherThanGoodwill_36" use="optional" order="48" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_EquityAndLiabilities" xlink:label="loc_ifrs-full_EquityAndLiabilities_54" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_EquityAndLiabilities_54" use="optional" order="49" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_Inventories" xlink:label="loc_ifrs-full_Inventories_685386" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_Inventories_685386" use="optional" order="50" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NoncurrentProvisionsForEmployeeBenefits" xlink:label="loc_ifrs-full_NoncurrentProvisionsForEmployeeBenefits_45" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_NoncurrentProvisionsForEmployeeBenefits_45" use="optional" order="51" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IncreaseDecreaseThroughSharebasedPaymentTransactions" xlink:label="loc_ifrs-full_IncreaseDecreaseThroughSharebasedPaymentTransactions_132" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_IncreaseDecreaseThroughSharebasedPaymentTransactions_132" use="optional" order="52" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_AccountingTreatmentOfTheShareSubscriptionAgreement" xlink:label="loc_argx_AccountingTreatmentOfTheShareSubscriptionAgreement_136" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_argx_AccountingTreatmentOfTheShareSubscriptionAgreement_136" use="optional" order="53" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_DecreaseIncreaseThroughTaxOnSharebasedPaymentTransactions" xlink:label="loc_ifrs-full_DecreaseIncreaseThroughTaxOnSharebasedPaymentTransactions_685469" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_DecreaseIncreaseThroughTaxOnSharebasedPaymentTransactions_685469" use="optional" order="54" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IssueOfEquity" xlink:label="loc_ifrs-full_IssueOfEquity_133" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_IssueOfEquity_133" use="optional" order="55" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ShareIssueRelatedCost" xlink:label="loc_ifrs-full_ShareIssueRelatedCost_135" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_ShareIssueRelatedCost_135" use="optional" order="56" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NoncurrentAssets" xlink:label="loc_ifrs-full_NoncurrentAssets_37" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_NoncurrentAssets_37" use="optional" order="57" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_DeferredIncomeClassifiedAsCurrent" xlink:label="loc_ifrs-full_DeferredIncomeClassifiedAsCurrent_52" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_DeferredIncomeClassifiedAsCurrent_52" use="optional" order="58" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_DeferredTaxAssets" xlink:label="loc_ifrs-full_DeferredTaxAssets_685392" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_DeferredTaxAssets_685392" use="optional" order="59" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_DeferredTaxLiabilities" xlink:label="loc_ifrs-full_DeferredTaxLiabilities_717830" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_DeferredTaxLiabilities_717830" use="optional" order="60" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OperatingExpense" xlink:label="loc_ifrs-full_OperatingExpense_685405" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_OperatingExpense_685405" use="optional" order="61" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_Assets" xlink:label="loc_ifrs-full_Assets_38" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_Assets_38" use="optional" order="62" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_TradeAndOtherCurrentPayables" xlink:label="loc_ifrs-full_TradeAndOtherCurrentPayables_50" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_TradeAndOtherCurrentPayables_50" use="optional" order="63" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_ResearchAndDevelopmentIncentiveReceivablesCurrent" xlink:label="loc_argx_ResearchAndDevelopmentIncentiveReceivablesCurrent_26" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_argx_ResearchAndDevelopmentIncentiveReceivablesCurrent_26" use="optional" order="64" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CurrentFinancialAssets" xlink:label="loc_ifrs-full_CurrentFinancialAssets_27" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_CurrentFinancialAssets_27" use="optional" order="65" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CurrentPrepaidExpenses" xlink:label="loc_ifrs-full_CurrentPrepaidExpenses_28" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_CurrentPrepaidExpenses_28" use="optional" order="66" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_TradeAndOtherCurrentReceivables" xlink:label="loc_ifrs-full_TradeAndOtherCurrentReceivables_29" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_TradeAndOtherCurrentReceivables_29" use="optional" order="67" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CurrentLeaseLiabilities" xlink:label="loc_ifrs-full_CurrentLeaseLiabilities_49" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_CurrentLeaseLiabilities_49" use="optional" order="68" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NoncurrentLeaseLiabilities" xlink:label="loc_ifrs-full_NoncurrentLeaseLiabilities_46" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_NoncurrentLeaseLiabilities_46" use="optional" order="69" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CurrentTaxLiabilitiesCurrent" xlink:label="loc_ifrs-full_CurrentTaxLiabilitiesCurrent_51" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_CurrentTaxLiabilitiesCurrent_51" use="optional" order="70" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_WeightedAverageShares" xlink:label="loc_ifrs-full_WeightedAverageShares_72" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_WeightedAverageShares_72" use="optional" order="71" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_Revenue" xlink:label="loc_ifrs-full_Revenue_58" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_Revenue_58" use="optional" order="72" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherOperatingIncomeExpense" xlink:label="loc_ifrs-full_OtherOperatingIncomeExpense_59" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_OtherOperatingIncomeExpense_59" use="optional" order="73" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_BasicAndDilutedEarningsLossPerShare" xlink:label="loc_ifrs-full_BasicAndDilutedEarningsLossPerShare_73" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_BasicAndDilutedEarningsLossPerShare_73" use="optional" order="74" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_GainsLossesOnExchangeDifferencesOnTranslationRecognisedInProfitOrLoss" xlink:label="loc_ifrs-full_GainsLossesOnExchangeDifferencesOnTranslationRecognisedInProfitOrLoss_67" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_GainsLossesOnExchangeDifferencesOnTranslationRecognisedInProfitOrLoss_67" use="optional" order="75" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_RevenueAndOperatingIncome" xlink:label="loc_ifrs-full_RevenueAndOperatingIncome_60" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_RevenueAndOperatingIncome_60" use="optional" order="76" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ProfitLossAttributableToOwnersOfParent" xlink:label="loc_ifrs-full_ProfitLossAttributableToOwnersOfParent_71" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_ProfitLossAttributableToOwnersOfParent_71" use="optional" order="77" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ResearchAndDevelopmentExpense" xlink:label="loc_ifrs-full_ResearchAndDevelopmentExpense_61" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_ResearchAndDevelopmentExpense_61" use="optional" order="78" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_SellingGeneralAndAdministrativeExpense" xlink:label="loc_ifrs-full_SellingGeneralAndAdministrativeExpense_62" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_SellingGeneralAndAdministrativeExpense_62" use="optional" order="79" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ProfitLossFromOperatingActivities" xlink:label="loc_ifrs-full_ProfitLossFromOperatingActivities_64" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_ProfitLossFromOperatingActivities_64" use="optional" order="80" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ComprehensiveIncomeAttributableToOwnersOfParent" xlink:label="loc_ifrs-full_ComprehensiveIncomeAttributableToOwnersOfParent_717856" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_ComprehensiveIncomeAttributableToOwnersOfParent_717856" use="optional" order="81" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CountryOfIncorporation" xlink:label="loc_ifrs-full_CountryOfIncorporation_7" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_CountryOfIncorporation_7" use="optional" order="82" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_FinanceIncomeCost" xlink:label="loc_ifrs-full_FinanceIncomeCost_65" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_FinanceIncomeCost_65" use="optional" order="83" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ProfitLossBeforeTax" xlink:label="loc_ifrs-full_ProfitLossBeforeTax_68" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_ProfitLossBeforeTax_68" use="optional" order="84" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IncomeTaxExpenseContinuingOperations" xlink:label="loc_ifrs-full_IncomeTaxExpenseContinuingOperations_69" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_IncomeTaxExpenseContinuingOperations_69" use="optional" order="85" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherComprehensiveIncomeNetOfTaxExchangeDifferencesOnTranslation" xlink:label="loc_ifrs-full_OtherComprehensiveIncomeNetOfTaxExchangeDifferencesOnTranslation_717839" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_OtherComprehensiveIncomeNetOfTaxExchangeDifferencesOnTranslation_717839" use="optional" order="86" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherComprehensiveIncomeNetOfTaxGainsLossesFromInvestmentsInEquityInstruments" xlink:label="loc_ifrs-full_OtherComprehensiveIncomeNetOfTaxGainsLossesFromInvestmentsInEquityInstruments_717842" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_OtherComprehensiveIncomeNetOfTaxGainsLossesFromInvestmentsInEquityInstruments_717842" use="optional" order="87" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NameOfParentEntity" xlink:label="loc_ifrs-full_NameOfParentEntity_6" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_NameOfParentEntity_6" use="optional" order="88" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_DescriptionOfNatureOfEntitysOperationsAndPrincipalActivities" xlink:label="loc_ifrs-full_DescriptionOfNatureOfEntitysOperationsAndPrincipalActivities_8" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_DescriptionOfNatureOfEntitysOperationsAndPrincipalActivities_8" use="optional" order="89" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_GainsLossesOnExchangeDifferencesOnTranslationNetOfTax" xlink:label="loc_ifrs-full_GainsLossesOnExchangeDifferencesOnTranslationNetOfTax_717838" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_GainsLossesOnExchangeDifferencesOnTranslationNetOfTax_717838" use="optional" order="90" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NameOfUltimateParentOfGroup" xlink:label="loc_ifrs-full_NameOfUltimateParentOfGroup_9" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_NameOfUltimateParentOfGroup_9" use="optional" order="91" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_DateOfEndOfReportingPeriod2013" xlink:label="loc_ifrs-full_DateOfEndOfReportingPeriod2013_10" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_DateOfEndOfReportingPeriod2013_10" use="optional" order="92" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_DomicileOfEntity" xlink:label="loc_ifrs-full_DomicileOfEntity_11" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_DomicileOfEntity_11" use="optional" order="93" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_LegalFormOfEntity" xlink:label="loc_ifrs-full_LegalFormOfEntity_12" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_LegalFormOfEntity_12" use="optional" order="94" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherComprehensiveIncome" xlink:label="loc_ifrs-full_OtherComprehensiveIncome_717843" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_OtherComprehensiveIncome_717843" use="optional" order="95" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ProfitLoss" xlink:label="loc_ifrs-full_ProfitLoss_717836" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_ProfitLoss_717836" use="optional" order="96" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NameOfReportingEntityOrOtherMeansOfIdentification" xlink:label="loc_ifrs-full_NameOfReportingEntityOrOtherMeansOfIdentification_3" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_NameOfReportingEntityOrOtherMeansOfIdentification_3" use="optional" order="97" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_PrincipalPlaceOfBusiness" xlink:label="loc_ifrs-full_PrincipalPlaceOfBusiness_4" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_PrincipalPlaceOfBusiness_4" use="optional" order="98" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_AddressOfRegisteredOfficeOfEntity" xlink:label="loc_ifrs-full_AddressOfRegisteredOfficeOfEntity_5" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_ifrs-full_AddressOfRegisteredOfficeOfEntity_5" use="optional" order="99" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_OtherReservesExcludingExchangeDifferencesOnTranslation" xlink:label="loc_argx_OtherReservesExcludingExchangeDifferencesOnTranslation_721172" />
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ifrs-full_AdjustmentsForFairValueGainsLosses_88" xlink:to="loc_argx_OtherReservesExcludingExchangeDifferencesOnTranslation_721172" use="optional" order="100" />
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.argenx.com/role/Anchoring">
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_AdjustmentsForDecreaseIncreaseInOtherAssets" xlink:label="AdjustmentsForDecreaseIncreaseInOtherAssets" xlink:title="AdjustmentsForDecreaseIncreaseInOtherAssets" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_AdjustmentsForDecreaseIncreaseInOtherNonCurrentAssets" xlink:label="AdjustmentsForDecreaseIncreaseInOtherNonCurrentAssets" xlink:title="AdjustmentsForDecreaseIncreaseInOtherNonCurrentAssets" />
<definitionArc xlink:type="arc" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" xlink:from="AdjustmentsForDecreaseIncreaseInOtherAssets" xlink:to="AdjustmentsForDecreaseIncreaseInOtherNonCurrentAssets" xlink:title="definition: AdjustmentsForDecreaseIncreaseInOtherAssets to AdjustmentsForDecreaseIncreaseInOtherNonCurrentAssets" order="1.0" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_AdjustmentsForDecreaseIncreaseInFinancialAssetsHeldForTrading" xlink:label="AdjustmentsForDecreaseIncreaseInFinancialAssetsHeldForTrading" xlink:title="AdjustmentsForDecreaseIncreaseInFinancialAssetsHeldForTrading" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_AdjustmentsForIncreaseDecreaseInFinancialAssetsCurrent" xlink:label="AdjustmentsForIncreaseDecreaseInFinancialAssetsCurrent" xlink:title="AdjustmentsForIncreaseDecreaseInFinancialAssetsCurrent" />
<definitionArc xlink:type="arc" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" xlink:from="AdjustmentsForDecreaseIncreaseInFinancialAssetsHeldForTrading" xlink:to="AdjustmentsForIncreaseDecreaseInFinancialAssetsCurrent" xlink:title="definition: AdjustmentsForDecreaseIncreaseInFinancialAssetsHeldForTrading to AdjustmentsForIncreaseDecreaseInFinancialAssetsCurrent" order="1.0" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_EffectOfExchangeRateChangesOnCashAndCashEquivalents" xlink:label="EffectOfExchangeRateChangesOnCashAndCashEquivalents" xlink:title="EffectOfExchangeRateChangesOnCashAndCashEquivalents" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_ExchangeGainFromCurrencyConversionOnProceedsFromIssueOfNewShare" xlink:label="ExchangeGainFromCurrencyConversionOnProceedsFromIssueOfNewShare" xlink:title="ExchangeGainFromCurrencyConversionOnProceedsFromIssueOfNewShare" />
<definitionArc xlink:type="arc" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" xlink:from="EffectOfExchangeRateChangesOnCashAndCashEquivalents" xlink:to="ExchangeGainFromCurrencyConversionOnProceedsFromIssueOfNewShare" xlink:title="definition: EffectOfExchangeRateChangesOnCashAndCashEquivalents to ExchangeGainFromCurrencyConversionOnProceedsFromIssueOfNewShare" order="1.0" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_NoncurrentAssets" xlink:label="NoncurrentAssets" xlink:title="NoncurrentAssets" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_ResearchAndDevelopmentIncentiveReceivablesNoncurrent" xlink:label="ResearchAndDevelopmentIncentiveReceivablesNoncurrent" xlink:title="ResearchAndDevelopmentIncentiveReceivablesNoncurrent" />
<definitionArc xlink:type="arc" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" xlink:from="NoncurrentAssets" xlink:to="ResearchAndDevelopmentIncentiveReceivablesNoncurrent" xlink:title="definition: NoncurrentAssets to ResearchAndDevelopmentIncentiveReceivablesNoncurrent" order="1.0" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_CurrentAssets" xlink:label="CurrentAssets" xlink:title="CurrentAssets" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_ResearchAndDevelopmentIncentiveReceivablesCurrent" xlink:label="ResearchAndDevelopmentIncentiveReceivablesCurrent" xlink:title="ResearchAndDevelopmentIncentiveReceivablesCurrent" />
<definitionArc xlink:type="arc" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" xlink:from="CurrentAssets" xlink:to="ResearchAndDevelopmentIncentiveReceivablesCurrent" xlink:title="definition: CurrentAssets to ResearchAndDevelopmentIncentiveReceivablesCurrent" order="1.0" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_OtherReserves" xlink:label="OtherReserves" xlink:title="OtherReserves" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_OtherReservesExcludingExchangeDifferencesOnTranslation" xlink:label="OtherReservesExcludingExchangeDifferencesOnTranslation" xlink:title="OtherReservesExcludingExchangeDifferencesOnTranslation" />
<definitionArc xlink:type="arc" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" xlink:from="OtherReserves" xlink:to="OtherReservesExcludingExchangeDifferencesOnTranslation" xlink:title="definition: OtherReserves to OtherReservesExcludingExchangeDifferencesOnTranslation" order="1.0" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_ReserveOfSharebasedPayments" xlink:label="ReserveOfSharebasedPayments" xlink:title="ReserveOfSharebasedPayments" />
<definitionArc xlink:type="arc" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" xlink:from="OtherReservesExcludingExchangeDifferencesOnTranslation" xlink:to="ReserveOfSharebasedPayments" xlink:title="definition: OtherReservesExcludingExchangeDifferencesOnTranslation to ReserveOfSharebasedPayments" order="2.0" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_AdjustmentsForIncreaseDecreaseInDeferredIncome" xlink:label="AdjustmentsForIncreaseDecreaseInDeferredIncome" xlink:title="AdjustmentsForIncreaseDecreaseInDeferredIncome" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_AdjustmentsForIncreaseDecreaseInDeferredRevenueCurrent" xlink:label="AdjustmentsForIncreaseDecreaseInDeferredRevenueCurrent" xlink:title="AdjustmentsForIncreaseDecreaseInDeferredRevenueCurrent" />
<definitionArc xlink:type="arc" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" xlink:from="AdjustmentsForIncreaseDecreaseInDeferredIncome" xlink:to="AdjustmentsForIncreaseDecreaseInDeferredRevenueCurrent" xlink:title="definition: AdjustmentsForIncreaseDecreaseInDeferredIncome to AdjustmentsForIncreaseDecreaseInDeferredRevenueCurrent" order="1.0" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_AdjustmentsForIncreaseDecreaseInDeferredRevenueNonCurrent" xlink:label="AdjustmentsForIncreaseDecreaseInDeferredRevenueNonCurrent" xlink:title="AdjustmentsForIncreaseDecreaseInDeferredRevenueNonCurrent" />
<definitionArc xlink:type="arc" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" xlink:from="AdjustmentsForIncreaseDecreaseInDeferredIncome" xlink:to="AdjustmentsForIncreaseDecreaseInDeferredRevenueNonCurrent" xlink:title="definition: AdjustmentsForIncreaseDecreaseInDeferredIncome to AdjustmentsForIncreaseDecreaseInDeferredRevenueNonCurrent" order="1.0" />
<loc xlink:type="locator" xlink:href="http://xbrl.ifrs.org/taxonomy/2020-03-16/full_ifrs/full_ifrs-cor_2020-03-16.xsd#ifrs-full_IncreaseDecreaseThroughTransfersAndOtherChangesEquity" xlink:label="IncreaseDecreaseThroughTransfersAndOtherChangesEquity" xlink:title="IncreaseDecreaseThroughTransfersAndOtherChangesEquity" />
<loc xlink:type="locator" xlink:href="7245009C5FZE6G9ODQ71-2021-12-31.xsd#argx_AccountingTreatmentOfTheShareSubscriptionAgreement" xlink:label="AccountingTreatmentOfTheShareSubscriptionAgreement" xlink:title="AccountingTreatmentOfTheShareSubscriptionAgreement" />
<definitionArc xlink:type="arc" xlink:arcrole="http://www.esma.europa.eu/xbrl/esef/arcrole/wider-narrower" xlink:from="IncreaseDecreaseThroughTransfersAndOtherChangesEquity" xlink:to="AccountingTreatmentOfTheShareSubscriptionAgreement" xlink:title="definition: IncreaseDecreaseThroughTransfersAndOtherChangesEquity to AccountingTreatmentOfTheShareSubscriptionAgreement" order="1.0" />
</definitionLink>
</linkbase>