diff --git a/lib/googleauth/service_account.rb b/lib/googleauth/service_account.rb
index f66abe3..03bc0cf 100644
--- a/lib/googleauth/service_account.rb
+++ b/lib/googleauth/service_account.rb
@@ -46,7 +46,7 @@ module Google
     #
     # cf [Application Default Credentials](http://goo.gl/mkAHpZ)
     class ServiceAccountCredentials < Signet::OAuth2::Client
-      TOKEN_CRED_URI = 'https://www.googleapis.com/oauth2/v3/token'.freeze
+      TOKEN_CRED_URI = 'https://www.googleapis.com/oauth2/v4/token'.freeze
       extend CredentialsLoader
 
       # Creates a ServiceAccountCredentials.
@@ -119,7 +119,7 @@ module Google
     class ServiceAccountJwtHeaderCredentials
       JWT_AUD_URI_KEY = :jwt_aud_uri
       AUTH_METADATA_KEY = Signet::OAuth2::AUTH_METADATA_KEY
-      TOKEN_CRED_URI = 'https://www.googleapis.com/oauth2/v3/token'.freeze
+      TOKEN_CRED_URI = 'https://www.googleapis.com/oauth2/v4/token'.freeze
       SIGNING_ALGORITHM = 'RS256'.freeze
       EXPIRY = 60
       extend CredentialsLoader
diff --git a/lib/googleauth/user_refresh.rb b/lib/googleauth/user_refresh.rb
index 14c1990..a54a4c9 100644
--- a/lib/googleauth/user_refresh.rb
+++ b/lib/googleauth/user_refresh.rb
@@ -46,7 +46,7 @@ module Google
     #
     # cf [Application Default Credentials](http://goo.gl/mkAHpZ)
     class UserRefreshCredentials < Signet::OAuth2::Client
-      TOKEN_CRED_URI = 'https://www.googleapis.com/oauth2/v3/token'.freeze
+      TOKEN_CRED_URI = 'https://www.googleapis.com/oauth2/v4/token'.freeze
       AUTHORIZATION_URI = 'https://accounts.google.com/o/oauth2/auth'.freeze
       REVOKE_TOKEN_URI = 'https://accounts.google.com/o/oauth2/revoke'.freeze
       extend CredentialsLoader
diff --git a/spec/googleauth/service_account_spec.rb b/spec/googleauth/service_account_spec.rb
index 8c569a1..679c0ef 100644
--- a/spec/googleauth/service_account_spec.rb
+++ b/spec/googleauth/service_account_spec.rb
@@ -137,7 +137,7 @@ describe Google::Auth::ServiceAccountCredentials do
       _claim, _header = JWT.decode(params.assoc('assertion').last,
                                    @key.public_key)
     end
-    stub_request(:post, 'https://www.googleapis.com/oauth2/v3/token')
+    stub_request(:post, 'https://www.googleapis.com/oauth2/v4/token')
       .with(body: hash_including(
         'grant_type' => 'urn:ietf:params:oauth:grant-type:jwt-bearer'
       ),
diff --git a/spec/googleauth/user_authorizer_spec.rb b/spec/googleauth/user_authorizer_spec.rb
index 5e8d62e..258dc30 100644
--- a/spec/googleauth/user_authorizer_spec.rb
+++ b/spec/googleauth/user_authorizer_spec.rb
@@ -242,7 +242,7 @@ describe Google::Auth::UserAuthorizer do
     end
 
     before(:example) do
-      stub_request(:post, 'https://www.googleapis.com/oauth2/v3/token')
+      stub_request(:post, 'https://www.googleapis.com/oauth2/v4/token')
         .to_return(body: token_json, status: 200, headers: {
                      'Content-Type' => 'application/json'
                    })
@@ -270,7 +270,7 @@ describe Google::Auth::UserAuthorizer do
 
   context 'with invalid authorization code' do
     before(:example) do
-      stub_request(:post, 'https://www.googleapis.com/oauth2/v3/token')
+      stub_request(:post, 'https://www.googleapis.com/oauth2/v4/token')
         .to_return(status: 400)
     end
 
diff --git a/spec/googleauth/user_refresh_spec.rb b/spec/googleauth/user_refresh_spec.rb
index d80f6ba..e68d3ce 100644
--- a/spec/googleauth/user_refresh_spec.rb
+++ b/spec/googleauth/user_refresh_spec.rb
@@ -68,7 +68,7 @@ describe Google::Auth::UserRefreshCredentials do
     body = MultiJson.dump('access_token' => access_token,
                           'token_type' => 'Bearer',
                           'expires_in' => 3600)
-    stub_request(:post, 'https://www.googleapis.com/oauth2/v3/token')
+    stub_request(:post, 'https://www.googleapis.com/oauth2/v4/token')
       .with(body: hash_including('grant_type' => 'refresh_token'))
       .to_return(body: body,
                  status: 200,
diff --git a/spec/googleauth/web_user_authorizer_spec.rb b/spec/googleauth/web_user_authorizer_spec.rb
index 04e30dd..4dd764b 100644
--- a/spec/googleauth/web_user_authorizer_spec.rb
+++ b/spec/googleauth/web_user_authorizer_spec.rb
@@ -107,7 +107,7 @@ describe Google::Auth::WebUserAuthorizer do
     end
 
     before(:example) do
-      stub_request(:post, 'https://www.googleapis.com/oauth2/v3/token')
+      stub_request(:post, 'https://www.googleapis.com/oauth2/v4/token')
         .to_return(body: token_json,
                    status: 200,
                    headers: { 'Content-Type' => 'application/json' })