diff --git a/packages/react/src/auth/index.ts b/packages/react/src/auth/index.ts
index 24520331..44c26463 100644
--- a/packages/react/src/auth/index.ts
+++ b/packages/react/src/auth/index.ts
@@ -20,7 +20,7 @@
 export { useSendSignInLinkToEmailMutation } from "./useSendSignInLinkToEmailMutation";
 export { useSignInAnonymouslyMutation } from "./useSignInAnonymouslyMutation";
 // useSignInWithCredentialMutation
-// useSignInWithCustomTokenMutation
+export { useSignInWithCustomTokenMutation } from "./useSignInWithCustomTokenMutation";
 // useSignInWithEmailAndPasswordMutation
 // useSignInWithEmailLinkMutation
 // useSignInWithPhoneNumberMutation
diff --git a/packages/react/src/auth/useSignInWithCustomTokenMutation.test.tsx b/packages/react/src/auth/useSignInWithCustomTokenMutation.test.tsx
new file mode 100644
index 00000000..c62ad608
--- /dev/null
+++ b/packages/react/src/auth/useSignInWithCustomTokenMutation.test.tsx
@@ -0,0 +1,39 @@
+import React from "react";
+import {
+  describe,
+  expect,
+  test,
+  beforeEach,
+  afterEach,
+  vi,
+  type MockInstance,
+} from "vitest";
+import { renderHook, act, waitFor } from "@testing-library/react";
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+import { useSignInWithCustomTokenMutation } from "./useSignInWithCustomTokenMutation";
+import { auth, wipeAuth } from "~/testing-utils";
+import {} from "firebase/auth";
+
+const queryClient = new QueryClient({
+  defaultOptions: {
+    queries: { retry: false },
+    mutations: { retry: false },
+  },
+});
+
+const wrapper = ({ children }: { children: React.ReactNode }) => (
+  <QueryClientProvider client={queryClient}>{children}</QueryClientProvider>
+);
+
+describe("useSignInWithCustomTokenMutation", () => {
+  beforeEach(async () => {
+    queryClient.clear();
+    await wipeAuth();
+  });
+
+  afterEach(async () => {
+    await auth.signOut();
+  });
+
+  test("successfully signs in with a valid custom token", async () => {});
+});
diff --git a/packages/react/src/auth/useSignInWithCustomTokenMutation.ts b/packages/react/src/auth/useSignInWithCustomTokenMutation.ts
new file mode 100644
index 00000000..8f4e32de
--- /dev/null
+++ b/packages/react/src/auth/useSignInWithCustomTokenMutation.ts
@@ -0,0 +1,23 @@
+import { useMutation, UseMutationOptions } from "@tanstack/react-query";
+import {
+  signInWithCustomToken,
+  type Auth,
+  type AuthError,
+  type UserCredential,
+} from "firebase/auth";
+
+type AuthUseMutationOptions<
+  TData = unknown,
+  TError = Error,
+  TVariables = void
+> = Omit<UseMutationOptions<TData, TError, TVariables>, "mutationFn">;
+
+export function useSignInWithCustomTokenMutation(
+  auth: Auth,
+  options?: AuthUseMutationOptions<UserCredential, AuthError, string>
+) {
+  return useMutation<UserCredential, AuthError, string>({
+    ...options,
+    mutationFn: (customToken) => signInWithCustomToken(auth, customToken),
+  });
+}