diff --git a/.changeset/thirty-rats-worry.md b/.changeset/thirty-rats-worry.md
new file mode 100644
index 00000000000..818a2a28e3f
--- /dev/null
+++ b/.changeset/thirty-rats-worry.md
@@ -0,0 +1,5 @@
+---
+"@firebase/auth": patch
+---
+
+Fix bug that caused onAuthStateChanged to be fired twice
diff --git a/packages/auth/src/core/auth/auth_impl.ts b/packages/auth/src/core/auth/auth_impl.ts
index af3258a8433..e34a845669e 100644
--- a/packages/auth/src/core/auth/auth_impl.ts
+++ b/packages/auth/src/core/auth/auth_impl.ts
@@ -139,6 +139,7 @@ export class AuthImpl implements AuthInternal, _FirebaseService {
       }
 
       await this.initializeCurrentUser(popupRedirectResolver);
+      this.lastNotifiedUid = this.currentUser?.uid || null;
 
       if (this._deleted) {
         return;
diff --git a/packages/auth/src/platform_browser/auth.test.ts b/packages/auth/src/platform_browser/auth.test.ts
index 3b33f357db2..7d75c8bca12 100644
--- a/packages/auth/src/platform_browser/auth.test.ts
+++ b/packages/auth/src/platform_browser/auth.test.ts
@@ -319,6 +319,25 @@ describe('core/auth/initializeAuth', () => {
       });
     });
 
+    it('initialization sets the callback UID correctly', async () => {
+      const stub = sinon.stub(
+        _getInstance<PersistenceInternal>(inMemoryPersistence)
+      );
+      stub._get.returns(Promise.resolve(testUser(oldAuth, 'uid').toJSON()));
+      let authStateChangeCalls = 0;
+
+      const auth = await initAndWait(inMemoryPersistence) as AuthInternal;
+      auth.onAuthStateChanged(() => {
+        authStateChangeCalls++;
+      });
+
+      await auth._updateCurrentUser(testUser(auth, 'uid'));
+      await new Promise(resolve => {
+        setTimeout(resolve, 200);
+      });
+      expect(authStateChangeCalls).to.eq(1);
+    });
+
     context('#tryRedirectSignIn', () => {
       it('returns null and clears the redirect user in case of error', async () => {
         const stub = sinon.stub(
diff --git a/packages/auth/test/integration/webdriver/persistence.test.ts b/packages/auth/test/integration/webdriver/persistence.test.ts
index 3ec3f553281..bc76609a0fa 100644
--- a/packages/auth/test/integration/webdriver/persistence.test.ts
+++ b/packages/auth/test/integration/webdriver/persistence.test.ts
@@ -445,7 +445,7 @@ browserDescribe('WebDriver persistence test', (driver, browser) => {
       await driver.call(CoreFunction.SIGN_OUT);
       expect(await driver.getUserSnapshot()).to.be.null;
       await driver.selectMainWindow({ noWait: true });
-      await driver.pause(500);
+      await driver.pause(700);
       expect(await driver.getUserSnapshot()).to.be.null;
 
       const cred2: UserCredential = await driver.call(