diff --git a/.changeset/light-queens-study.md b/.changeset/light-queens-study.md
new file mode 100644
index 00000000000..a845151cc84
--- /dev/null
+++ b/.changeset/light-queens-study.md
@@ -0,0 +1,2 @@
+---
+---
diff --git a/integration/.keys.json.sample b/integration/.keys.json.sample
index b3ac43f1347..67761bfa903 100644
--- a/integration/.keys.json.sample
+++ b/integration/.keys.json.sample
@@ -62,5 +62,9 @@
   "with-protect-service": {
     "pk": "",
     "sk": ""
+  },
+  "with-enterprise-sso": {
+    "pk": "",
+    "sk": ""
   }
 }
diff --git a/integration/presets/envs.ts b/integration/presets/envs.ts
index 7d13f64c7e4..5c87b72647c 100644
--- a/integration/presets/envs.ts
+++ b/integration/presets/envs.ts
@@ -119,6 +119,14 @@ const withSharedUIVariant = withEmailCodes
 
 const withEmailLinks = withInstanceKeys('with-email-links', base.clone().setId('withEmailLinks'));
 
+const withEnterpriseSso = withInstanceKeys(
+  'with-enterprise-sso',
+  base
+    .clone()
+    .setId('withEnterpriseSso')
+    .setEnvVariable('private', 'CLERK_ENCRYPTION_KEY', constants.E2E_CLERK_ENCRYPTION_KEY || 'a-key'),
+);
+
 const withCustomRoles = withInstanceKeys(
   'with-custom-roles',
   base
@@ -252,6 +260,7 @@ export const envs = {
   withEmailCodesProxy,
   withEmailCodesQuickstart,
   withEmailLinks,
+  withEnterpriseSso,
   withKeyless,
   withLegalConsent,
   withNeedsClientTrust,
diff --git a/integration/presets/longRunningApps.ts b/integration/presets/longRunningApps.ts
index 66cc6bf5ca6..208e3f71148 100644
--- a/integration/presets/longRunningApps.ts
+++ b/integration/presets/longRunningApps.ts
@@ -74,6 +74,7 @@ export const createLongRunningApps = () => {
     { id: 'tanstack.react-start', config: tanstack.reactStart, env: envs.withEmailCodes },
     { id: 'tanstack.react-start.withCustomRoles', config: tanstack.reactStart, env: envs.withCustomRoles },
     { id: 'tanstack.react-start.withEmailCodesProxy', config: tanstack.reactStart, env: envs.withEmailCodesProxy },
+    { id: 'tanstack.react-start.withEnterpriseSso', config: tanstack.reactStart, env: envs.withEnterpriseSso },
 
     /**
      * Various apps - basic flows
diff --git a/integration/tests/tanstack-start/enterprise-sso.test.ts b/integration/tests/tanstack-start/enterprise-sso.test.ts
new file mode 100644
index 00000000000..5b29d31cc7d
--- /dev/null
+++ b/integration/tests/tanstack-start/enterprise-sso.test.ts
@@ -0,0 +1,88 @@
+import type { EnterpriseConnection } from '@clerk/backend';
+import { expect, test } from '@playwright/test';
+
+import { appConfigs } from '../../presets';
+import { createTestUtils, testAgainstRunningApps } from '../../testUtils';
+
+// Self-signed certificate for the fake SAML IdP (required to activate enterprise connections)
+const FAKE_IDP_CERTIFICATE =
+  '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';
+
+/**
+ * Helper to create and activate a SAML enterprise connection.
+ * The Clerk API requires creating the connection first (inactive), then activating via update.
+ * The `provider` field is required by the API but missing from the SDK types, so we cast.
+ */
+async function createActiveEnterpriseConnection(
+  clerk: ReturnType<typeof createTestUtils>['services']['clerk'],
+  opts: { name: string; domain: string; idpEntityId: string; idpSsoUrl: string },
+): Promise<EnterpriseConnection> {
+  const conn = await clerk.enterpriseConnections.createEnterpriseConnection({
+    name: opts.name,
+    domains: [opts.domain],
+    provider: 'saml_custom',
+    saml: {
+      idpEntityId: opts.idpEntityId,
+      idpSsoUrl: opts.idpSsoUrl,
+      idpCertificate: FAKE_IDP_CERTIFICATE,
+    },
+  } as Parameters<typeof clerk.enterpriseConnections.createEnterpriseConnection>[0]);
+
+  return clerk.enterpriseConnections.updateEnterpriseConnection(conn.id, { active: true });
+}
+
+testAgainstRunningApps({ withEnv: [appConfigs.envs.withEnterpriseSso] })(
+  'enterprise SSO tests for @tanstack-react-start',
+  ({ app }) => {
+    test.describe.configure({ mode: 'serial' });
+
+    const testDomain = 'e2e-enterprise-test.dev';
+    const fakeIdpHost = `fake-idp.${testDomain}`;
+    let enterpriseConnection: EnterpriseConnection;
+
+    test.beforeAll(async () => {
+      const u = createTestUtils({ app });
+      enterpriseConnection = await createActiveEnterpriseConnection(u.services.clerk, {
+        name: 'E2E Test SAML Connection',
+        domain: testDomain,
+        idpEntityId: `https://${fakeIdpHost}`,
+        idpSsoUrl: `https://${fakeIdpHost}/sso`,
+      });
+    });
+
+    test.afterAll(async () => {
+      const u = createTestUtils({ app });
+      await u.services.clerk.enterpriseConnections.deleteEnterpriseConnection(enterpriseConnection.id);
+      await app.teardown();
+    });
+
+    test('sign-in with enterprise domain email initiates SSO redirect', async ({ page, context }) => {
+      const u = createTestUtils({ app, page, context });
+
+      // Capture the redirect to the fake IdP (proves enterprise SSO kicked in)
+      const idpRequestPromise = page.waitForRequest(req => req.url().includes(fakeIdpHost));
+
+      await u.po.signIn.goTo();
+      await u.po.signIn.setIdentifier(`testuser@${testDomain}`);
+      await u.po.signIn.continue();
+
+      // Verify the browser was redirected to the enterprise IdP
+      const idpRequest = await idpRequestPromise;
+      expect(idpRequest.url()).toContain(fakeIdpHost);
+    });
+
+    test('non-managed domain email does not trigger SSO redirect', async ({ page, context }) => {
+      const u = createTestUtils({ app, page, context });
+
+      await u.po.signIn.goTo();
+      await u.po.signIn.setIdentifier('testuser@regular-domain.com');
+      await u.po.signIn.continue();
+
+      // The sign-in form should remain visible (no redirect to an IdP)
+      await u.po.signIn.waitForMounted();
+
+      // URL should still be on the app's sign-in page, not redirected externally
+      expect(page.url()).toContain('/sign-in');
+    });
+  },
+);