diff --git a/.changeset/curly-mirrors-occur.md b/.changeset/curly-mirrors-occur.md
new file mode 100644
index 00000000000..04f571bc07d
--- /dev/null
+++ b/.changeset/curly-mirrors-occur.md
@@ -0,0 +1,5 @@
+---
+'@firebase/auth': patch
+---
+
+Included a reference to AuthInternal in MultiFactorSessionImpl.
diff --git a/packages/auth/src/mfa/mfa_session.ts b/packages/auth/src/mfa/mfa_session.ts
index f9b8452d06d..eeb308b70e1 100644
--- a/packages/auth/src/mfa/mfa_session.ts
+++ b/packages/auth/src/mfa/mfa_session.ts
@@ -14,6 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+import { AuthInternal } from '../model/auth';
 import { MultiFactorSession } from '../model/public_types';
 
 export const enum MultiFactorSessionType {
@@ -31,11 +32,19 @@ interface SerializedMultiFactorSession {
 export class MultiFactorSessionImpl implements MultiFactorSession {
   private constructor(
     readonly type: MultiFactorSessionType,
-    readonly credential: string
+    readonly credential: string,
+    readonly auth?: AuthInternal
   ) {}
 
-  static _fromIdtoken(idToken: string): MultiFactorSessionImpl {
-    return new MultiFactorSessionImpl(MultiFactorSessionType.ENROLL, idToken);
+  static _fromIdtoken(
+    idToken: string,
+    auth?: AuthInternal
+  ): MultiFactorSessionImpl {
+    return new MultiFactorSessionImpl(
+      MultiFactorSessionType.ENROLL,
+      idToken,
+      auth
+    );
   }
 
   static _fromMfaPendingCredential(
diff --git a/packages/auth/src/mfa/mfa_user.test.ts b/packages/auth/src/mfa/mfa_user.test.ts
index a21b0d27b51..2c0da80a11a 100644
--- a/packages/auth/src/mfa/mfa_user.test.ts
+++ b/packages/auth/src/mfa/mfa_user.test.ts
@@ -84,6 +84,12 @@ describe('core/mfa/mfa_user/MultiFactorUser', () => {
       expect(mfaSession.type).to.eq(MultiFactorSessionType.ENROLL);
       expect(mfaSession.credential).to.eq('access-token');
     });
+    it('should contain a reference to auth', async () => {
+      const mfaSession = (await mfaUser.getSession()) as MultiFactorSessionImpl;
+      expect(mfaSession.type).to.eq(MultiFactorSessionType.ENROLL);
+      expect(mfaSession.credential).to.eq('access-token');
+      expect(mfaSession.auth).to.eq(auth);
+    });
   });
 
   describe('enroll', () => {
diff --git a/packages/auth/src/mfa/mfa_user.ts b/packages/auth/src/mfa/mfa_user.ts
index 55bd15f830b..535de17310d 100644
--- a/packages/auth/src/mfa/mfa_user.ts
+++ b/packages/auth/src/mfa/mfa_user.ts
@@ -49,7 +49,10 @@ export class MultiFactorUserImpl implements MultiFactorUser {
   }
 
   async getSession(): Promise<MultiFactorSession> {
-    return MultiFactorSessionImpl._fromIdtoken(await this.user.getIdToken());
+    return MultiFactorSessionImpl._fromIdtoken(
+      await this.user.getIdToken(),
+      this.user.auth
+    );
   }
 
   async enroll(
diff --git a/packages/auth/src/platform_browser/mfa/assertions/phone.test.ts b/packages/auth/src/platform_browser/mfa/assertions/phone.test.ts
index 22e64593cfd..778d47705d8 100644
--- a/packages/auth/src/platform_browser/mfa/assertions/phone.test.ts
+++ b/packages/auth/src/platform_browser/mfa/assertions/phone.test.ts
@@ -58,7 +58,10 @@ describe('platform_browser/mfa/phone', () => {
 
   describe('enroll', () => {
     beforeEach(() => {
-      session = MultiFactorSessionImpl._fromIdtoken('enrollment-id-token');
+      session = MultiFactorSessionImpl._fromIdtoken(
+        'enrollment-id-token',
+        auth
+      );
     });
 
     it('should finalize the MFA enrollment', async () => {
@@ -75,6 +78,7 @@ describe('platform_browser/mfa/phone', () => {
           sessionInfo: 'verification-id'
         }
       });
+      expect(session.auth).to.eql(auth);
     });
 
     context('with display name', () => {
@@ -97,6 +101,7 @@ describe('platform_browser/mfa/phone', () => {
             sessionInfo: 'verification-id'
           }
         });
+        expect(session.auth).to.eql(auth);
       });
     });
   });
@@ -119,6 +124,7 @@ describe('platform_browser/mfa/phone', () => {
           sessionInfo: 'verification-id'
         }
       });
+      expect(session.auth).to.eql(undefined);
     });
   });
 });