diff --git a/packages/google_sign_in/google_sign_in/CHANGELOG.md b/packages/google_sign_in/google_sign_in/CHANGELOG.md
index a0d2d470020d..b3c3955cf50a 100644
--- a/packages/google_sign_in/google_sign_in/CHANGELOG.md
+++ b/packages/google_sign_in/google_sign_in/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 4.5.0
+
+* Add support for getting `serverAuthCode`.
+
 ## 4.4.6
 
 * Update lower bound of dart dependency to 2.1.0.
diff --git a/packages/google_sign_in/google_sign_in/android/src/main/java/io/flutter/plugins/googlesignin/GoogleSignInPlugin.java b/packages/google_sign_in/google_sign_in/android/src/main/java/io/flutter/plugins/googlesignin/GoogleSignInPlugin.java
index e8fcd29075e3..ce04e595080b 100755
--- a/packages/google_sign_in/google_sign_in/android/src/main/java/io/flutter/plugins/googlesignin/GoogleSignInPlugin.java
+++ b/packages/google_sign_in/google_sign_in/android/src/main/java/io/flutter/plugins/googlesignin/GoogleSignInPlugin.java
@@ -335,6 +335,7 @@ public void init(
                 .getIdentifier("default_web_client_id", "string", context.getPackageName());
         if (clientIdIdentifier != 0) {
           optionsBuilder.requestIdToken(context.getString(clientIdIdentifier));
+          optionsBuilder.requestServerAuthCode(context.getString(clientIdIdentifier));
         }
         for (String scope : requestedScopes) {
           optionsBuilder.requestScopes(new Scope(scope));
@@ -484,6 +485,7 @@ private void onSignInAccount(GoogleSignInAccount account) {
       response.put("email", account.getEmail());
       response.put("id", account.getId());
       response.put("idToken", account.getIdToken());
+      response.put("serverAuthCode", account.getServerAuthCode());
       response.put("displayName", account.getDisplayName());
       if (account.getPhotoUrl() != null) {
         response.put("photoUrl", account.getPhotoUrl().toString());
diff --git a/packages/google_sign_in/google_sign_in/example/android/app/src/main/res/values/strings.xml b/packages/google_sign_in/google_sign_in/example/android/app/src/main/res/values/strings.xml
new file mode 100644
index 000000000000..c7e28ffcedd1
--- /dev/null
+++ b/packages/google_sign_in/google_sign_in/example/android/app/src/main/res/values/strings.xml
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string name="default_web_client_id">YOUR_WEB_CLIENT_ID</string>
+</resources>
diff --git a/packages/google_sign_in/google_sign_in/example/ios/Runner/GoogleService-Info.plist b/packages/google_sign_in/google_sign_in/example/ios/Runner/GoogleService-Info.plist
index 8d24ccc9b130..6042aab908af 100644
--- a/packages/google_sign_in/google_sign_in/example/ios/Runner/GoogleService-Info.plist
+++ b/packages/google_sign_in/google_sign_in/example/ios/Runner/GoogleService-Info.plist
@@ -38,5 +38,7 @@
 	<string>1:479882132969:ios:2643f950e0a0da08</string>
 	<key>DATABASE_URL</key>
 	<string>https://my-flutter-proj.firebaseio.com</string>
+	<key>SERVER_CLIENT_ID</key>
+	<string>YOUR_SERVER_CLIENT_ID</string>
 </dict>
 </plist>
\ No newline at end of file
diff --git a/packages/google_sign_in/google_sign_in/ios/Classes/FLTGoogleSignInPlugin.m b/packages/google_sign_in/google_sign_in/ios/Classes/FLTGoogleSignInPlugin.m
index 9049fcd62a33..f621d1e68312 100644
--- a/packages/google_sign_in/google_sign_in/ios/Classes/FLTGoogleSignInPlugin.m
+++ b/packages/google_sign_in/google_sign_in/ios/Classes/FLTGoogleSignInPlugin.m
@@ -10,6 +10,8 @@
 // for more info.
 static NSString *const kClientIdKey = @"CLIENT_ID";
 
+static NSString *const kServerClientIdKey = @"SERVER_CLIENT_ID";
+
 // These error codes must match with ones declared on Android and Dart sides.
 static NSString *const kErrorReasonSignInRequired = @"sign_in_required";
 static NSString *const kErrorReasonSignInCanceled = @"sign_in_canceled";
@@ -76,6 +78,7 @@ - (void)handleMethodCall:(FlutterMethodCall *)call result:(FlutterResult)result
       if (path) {
         NSMutableDictionary *plist = [[NSMutableDictionary alloc] initWithContentsOfFile:path];
         [GIDSignIn sharedInstance].clientID = plist[kClientIdKey];
+        [GIDSignIn sharedInstance].serverClientID = plist[kServerClientIdKey];
         [GIDSignIn sharedInstance].scopes = call.arguments[@"scopes"];
         [GIDSignIn sharedInstance].hostedDomain = call.arguments[@"hostedDomain"];
         result(nil);
@@ -221,6 +224,7 @@ - (void)signIn:(GIDSignIn *)signIn
         @"email" : user.profile.email ?: [NSNull null],
         @"id" : user.userID ?: [NSNull null],
         @"photoUrl" : [photoUrl absoluteString] ?: [NSNull null],
+        @"serverAuthCode" : user.serverAuthCode ?: [NSNull null]
       }
                          error:nil];
     }
diff --git a/packages/google_sign_in/google_sign_in/lib/google_sign_in.dart b/packages/google_sign_in/google_sign_in/lib/google_sign_in.dart
index 7402c7a69816..0f1f15bbb8c4 100644
--- a/packages/google_sign_in/google_sign_in/lib/google_sign_in.dart
+++ b/packages/google_sign_in/google_sign_in/lib/google_sign_in.dart
@@ -27,6 +27,9 @@ class GoogleSignInAuthentication {
   /// The OAuth2 access token to access Google services.
   String get accessToken => _data.accessToken;
 
+  /// Server auth code used to access Google Login
+  String get serverAuthCode => _data.serverAuthCode;
+
   @override
   String toString() => 'GoogleSignInAuthentication:$_data';
 }
diff --git a/packages/google_sign_in/google_sign_in/pubspec.yaml b/packages/google_sign_in/google_sign_in/pubspec.yaml
index e02c8ee17f11..b82a2bd74856 100644
--- a/packages/google_sign_in/google_sign_in/pubspec.yaml
+++ b/packages/google_sign_in/google_sign_in/pubspec.yaml
@@ -2,7 +2,7 @@ name: google_sign_in
 description: Flutter plugin for Google Sign-In, a secure authentication system
   for signing in with a Google account on Android and iOS.
 homepage: https://github.com/flutter/plugins/tree/master/packages/google_sign_in/google_sign_in
-version: 4.4.6
+version: 4.5.0
 
 flutter:
   plugin:
@@ -16,7 +16,7 @@ flutter:
         default_package: google_sign_in_web
 
 dependencies:
-  google_sign_in_platform_interface: ^1.1.0
+  google_sign_in_platform_interface: ^1.1.1
   flutter:
     sdk: flutter
   meta: ^1.0.4
diff --git a/packages/google_sign_in/google_sign_in/test/google_sign_in_test.dart b/packages/google_sign_in/google_sign_in/test/google_sign_in_test.dart
index 898c27fd9f7e..5969edbaba76 100755
--- a/packages/google_sign_in/google_sign_in/test/google_sign_in_test.dart
+++ b/packages/google_sign_in/google_sign_in/test/google_sign_in_test.dart
@@ -36,6 +36,7 @@ void main() {
       'getTokens': <dynamic, dynamic>{
         'idToken': '123',
         'accessToken': '456',
+        'serverAuthCode': '789',
       },
     };
 
@@ -370,6 +371,7 @@ void main() {
 
       expect(auth.accessToken, '456');
       expect(auth.idToken, '123');
+      expect(auth.serverAuthCode, '789');
       expect(
         log,
         <Matcher>[