diff --git a/.changeset/expo-local-credentials-padded-publishable-key.md b/.changeset/expo-local-credentials-padded-publishable-key.md
new file mode 100644
index 00000000000..c4116fbc1ae
--- /dev/null
+++ b/.changeset/expo-local-credentials-padded-publishable-key.md
@@ -0,0 +1,5 @@
+---
+'@clerk/expo': patch
+---
+
+Fix `useLocalCredentials` throwing "Invalid key provided to SecureStore" when the publishable key ends with base64 padding (`=`).
diff --git a/packages/expo/src/local-credentials/useLocalCredentials/__tests__/useLocalCredentials.test.ts b/packages/expo/src/local-credentials/useLocalCredentials/__tests__/useLocalCredentials.test.ts
index f560de6d005..9cdcc567bf0 100644
--- a/packages/expo/src/local-credentials/useLocalCredentials/__tests__/useLocalCredentials.test.ts
+++ b/packages/expo/src/local-credentials/useLocalCredentials/__tests__/useLocalCredentials.test.ts
@@ -33,15 +33,29 @@ vi.mock('expo-local-authentication', () => ({
   supportedAuthenticationTypesAsync: () => Promise.resolve([]),
 }));
 
+const assertValidKey = (key: string) => {
+  if (!/^[\w.-]+$/.test(key)) {
+    throw new Error('Invalid key provided to SecureStore.');
+  }
+};
+
 vi.mock('expo-secure-store', () => ({
   WHEN_PASSCODE_SET_THIS_DEVICE_ONLY: 0,
-  getItem: (key: string) => mocks.store.get(key) ?? null,
-  getItemAsync: (key: string) => Promise.resolve(mocks.store.get(key) ?? null),
+  getItem: (key: string) => {
+    assertValidKey(key);
+    return mocks.store.get(key) ?? null;
+  },
+  getItemAsync: (key: string) => {
+    assertValidKey(key);
+    return Promise.resolve(mocks.store.get(key) ?? null);
+  },
   deleteItemAsync: (key: string) => {
+    assertValidKey(key);
     mocks.store.delete(key);
     return Promise.resolve();
   },
   setItemAsync: (key: string, value: string, options?: { requireAuthentication?: boolean }) => {
+    assertValidKey(key);
     if (options?.requireAuthentication && mocks.rejectProtectedWrites) {
       return Promise.reject(new Error('User canceled the authentication'));
     }
@@ -54,11 +68,25 @@ const identifierKey = `__clerk_local_auth_${mocks.publishableKey}_identifier`;
 const passwordKey = `__clerk_local_auth_${mocks.publishableKey}_password`;
 
 beforeEach(() => {
+  mocks.publishableKey = 'pk_test_Zm9vLmNsZXJrLmFjY291bnRzLmRldiQ';
   mocks.store.clear();
   mocks.rejectProtectedWrites = false;
 });
 
 describe('useLocalCredentials', () => {
+  test('stores credentials when the publishable key has base64 padding', async () => {
+    mocks.publishableKey = `pk_test_${btoa('ab.clerk.accounts.dev$')}`;
+    expect(mocks.publishableKey.endsWith('=')).toBe(true);
+
+    const { result } = renderHook(() => useLocalCredentials());
+    await act(() => result.current.setCredentials({ identifier: 'user@example.com', password: 'hunter2' }));
+
+    expect(result.current.hasCredentials).toBe(true);
+    for (const storedKey of mocks.store.keys()) {
+      expect(storedKey).toMatch(/^[\w.-]+$/);
+    }
+  });
+
   test('reports credentials once both writes succeed', async () => {
     const { result } = renderHook(() => useLocalCredentials());
 
diff --git a/packages/expo/src/local-credentials/useLocalCredentials/useLocalCredentials.ts b/packages/expo/src/local-credentials/useLocalCredentials/useLocalCredentials.ts
index bd38a552502..0e3925bec1c 100644
--- a/packages/expo/src/local-credentials/useLocalCredentials/useLocalCredentials.ts
+++ b/packages/expo/src/local-credentials/useLocalCredentials/useLocalCredentials.ts
@@ -114,8 +114,9 @@ export const useLocalCredentials = (): LocalCredentialsReturn => {
   const { isLoaded, signIn } = useSignIn();
   const { publishableKey } = useClerk();
 
-  const key = `__clerk_local_auth_${publishableKey}_identifier`;
-  const pkey = `__clerk_local_auth_${publishableKey}_password`;
+  const storeKeyBase = publishableKey.split('=').join('');
+  const key = `__clerk_local_auth_${storeKeyBase}_identifier`;
+  const pkey = `__clerk_local_auth_${storeKeyBase}_password`;
   const [hasLocalAuthCredentials, setHasLocalAuthCredentials] = useState(!!getItem(key));
   const [userOwnsCredentials, setUserOwnsCredentials] = useUserOwnsCredentials({ storeKey: key });
   const hasEnrolledBiometric = useEnrolledBiometric();