diff --git a/packages/transaction-pay-controller/CHANGELOG.md b/packages/transaction-pay-controller/CHANGELOG.md
index 9bc8d7c2286..57fb0f513aa 100644
--- a/packages/transaction-pay-controller/CHANGELOG.md
+++ b/packages/transaction-pay-controller/CHANGELOG.md
@@ -11,6 +11,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Bump `@metamask/keyring-controller` from `^27.0.0` to `^27.1.0` ([#9129](https://github.com/MetaMask/core/pull/9129))
 
+### Fixed
+
+- Mark MM Pay transactions as externally signed when quotes are available ([#9145](https://github.com/MetaMask/core/pull/9145))
+
 ## [23.7.0]
 
 ### Added
diff --git a/packages/transaction-pay-controller/src/utils/quotes.test.ts b/packages/transaction-pay-controller/src/utils/quotes.test.ts
index 937b03235e1..69fe2675497 100644
--- a/packages/transaction-pay-controller/src/utils/quotes.test.ts
+++ b/packages/transaction-pay-controller/src/utils/quotes.test.ts
@@ -730,6 +730,30 @@ describe('Quotes Utils', () => {
       );
     });
 
+    it('marks the transaction as externally signed when quotes are available so the publish hook owns submission', async () => {
+      await run();
+
+      const transactionMetaMock = {} as TransactionMeta;
+      updateTransactionMock.mock.calls[0][1](transactionMetaMock);
+
+      expect(transactionMetaMock).toMatchObject(
+        expect.objectContaining({ isExternalSign: true }),
+      );
+    });
+
+    it('clears the externally signed flag when no quotes are returned so the transaction falls back to local signing', async () => {
+      getQuotesMock.mockResolvedValue([]);
+
+      await run();
+
+      const transactionMetaMock = {} as TransactionMeta;
+      updateTransactionMock.mock.calls[0][1](transactionMetaMock);
+
+      expect(transactionMetaMock).toMatchObject(
+        expect.objectContaining({ isExternalSign: false }),
+      );
+    });
+
     it('updates metrics in metadata', async () => {
       await run();
 
diff --git a/packages/transaction-pay-controller/src/utils/quotes.ts b/packages/transaction-pay-controller/src/utils/quotes.ts
index 319bbbc71ca..098911a2de1 100644
--- a/packages/transaction-pay-controller/src/utils/quotes.ts
+++ b/packages/transaction-pay-controller/src/utils/quotes.ts
@@ -163,6 +163,7 @@ export async function updateQuotes(
 
     syncTransaction({
       batchTransactions,
+      hasQuotes: quotes.length > 0,
       isPostQuote,
       messenger: messenger as never,
       paymentToken,
@@ -198,6 +199,7 @@ export async function updateQuotes(
  *
  * @param request - Request object.
  * @param request.batchTransactions - Batch transactions to sync.
+ * @param request.hasQuotes - Whether MM Pay produced any quotes for this transaction.
  * @param request.isPostQuote - Whether this is a post-quote flow.
  * @param request.messenger - Messenger instance.
  * @param request.paymentToken - Payment token (source for standard flows, destination for post-quote).
@@ -206,6 +208,7 @@ export async function updateQuotes(
  */
 function syncTransaction({
   batchTransactions,
+  hasQuotes,
   isPostQuote,
   messenger,
   paymentToken,
@@ -213,6 +216,7 @@ function syncTransaction({
   transactionId,
 }: {
   batchTransactions: BatchTransaction[];
+  hasQuotes: boolean;
   isPostQuote?: boolean;
   messenger: TransactionPayControllerMessenger;
   paymentToken: TransactionPaymentToken | undefined;
@@ -233,6 +237,14 @@ function syncTransaction({
       tx.batchTransactions = batchTransactions;
       tx.batchTransactionsOptions = {};
 
+      // When MM Pay has produced quotes, it owns submission of this transaction
+      // via its strategy publish hook, so the parent must be marked externally
+      // signed to skip the local `KeyringController:signTransaction` call.
+      // When there are no quotes (e.g. user selected the target token as the
+      // payment token in a Predict flow), the transaction falls back to normal
+      // local signing, so the flag is cleared to allow that.
+      tx.isExternalSign = hasQuotes;
+
       tx.metamaskPay = {
         bridgeFeeFiat: totals.fees.provider.usd,
         chainId: paymentToken.chainId,