diff --git a/src/libs/actions/IOU/PayMoneyRequest.ts b/src/libs/actions/IOU/PayMoneyRequest.ts
index 8b5752eff080..93bca67d72d4 100644
--- a/src/libs/actions/IOU/PayMoneyRequest.ts
+++ b/src/libs/actions/IOU/PayMoneyRequest.ts
@@ -773,10 +773,15 @@ function completePaymentOnboarding(
         onboardingPurpose = CONST.ONBOARDING_CHOICES.CHAT_SPLIT;
     }
     const {onboardingMessages} = getOnboardingMessages();
+    // choice can hold a backend value with no onboarding message (e.g. classicAdmin for Classic-invited admins), so skip instead of crashing on the undefined lookup below.
+    const onboardingMessage = onboardingMessages[onboardingPurpose];
+    if (!onboardingMessage) {
+        return;
+    }
 
     completeOnboarding({
         engagementChoice: onboardingPurpose,
-        onboardingMessage: onboardingMessages[onboardingPurpose],
+        onboardingMessage,
         firstName: personalDetails?.firstName,
         lastName: personalDetails?.lastName,
         adminsChatReportID,
diff --git a/tests/actions/IOUTest/PayMoneyRequestTest.ts b/tests/actions/IOUTest/PayMoneyRequestTest.ts
index 4db333dd6bc2..5da07aaf6e7d 100644
--- a/tests/actions/IOUTest/PayMoneyRequestTest.ts
+++ b/tests/actions/IOUTest/PayMoneyRequestTest.ts
@@ -2018,5 +2018,17 @@ describe('actions/IOU/PayMoneyRequest', () => {
                 }),
             );
         });
+
+        it('does not call completeOnboarding when the choice has no onboarding message (e.g. classicAdmin for Classic-invited admins)', () => {
+            const introSelected: IntroSelected = {
+                // @ts-expect-error classicAdmin is a backend-only choice value with no App onboarding message, intentionally outside the OnboardingPurpose union
+                choice: 'classicAdmin',
+                inviteType: CONST.ONBOARDING_INVITE_TYPES.WORKSPACE,
+                isInviteOnboardingComplete: false,
+            };
+
+            expect(() => completePaymentOnboarding(CONST.PAYMENT_SELECTED.PBA, introSelected, false, [CONST.BETAS.ALL], CARLOS_ACCOUNT_ID)).not.toThrow();
+            expect(completeOnboardingSpy).not.toHaveBeenCalled();
+        });
     });
 });