diff --git a/cinder/backup/drivers/gcs.py b/cinder/backup/drivers/gcs.py
index 9eb92fa18d6..cc3aa662b84 100644
--- a/cinder/backup/drivers/gcs.py
+++ b/cinder/backup/drivers/gcs.py
@@ -37,11 +37,6 @@ try:
 except ImportError:
     service_account = google_auth_httplib2 = gexceptions = None
 
-try:
-    from oauth2client import client
-except ImportError:
-    client = None
-
 from googleapiclient import discovery
 from googleapiclient import errors
 from googleapiclient import http
@@ -176,16 +171,14 @@ class GoogleBackupDriver(chunkeddriver.ChunkedBackupDriver):
             creds = service_account.Credentials.from_service_account_file(
                 backup_credential)
             OAUTH_EXCEPTIONS = (gexceptions.RefreshError,
-                                gexceptions.DefaultCredentialsError,
-                                client.Error)
-        # The (deprecated) client is imported if the oauth2client library is
-        # available
-        elif client:
-            creds = client.GoogleCredentials.from_stream(backup_credential)
-            OAUTH_EXCEPTIONS = client.Error
+                                gexceptions.DefaultCredentialsError)
         else:
-            msg = _('google-auth-httplib2 or oauth2client should be '
-                    'installed.')
+            # NOTE(tkajinam): google-api-python-client is now in requirements
+            #                 and google-auth-httplib2 is its dependency. So
+            #                 this error should not be raised now. But it's
+            #                 kept now in case the client library is moved to
+            #                 extra dependencies
+            msg = _('google-api-python-client not found')
             raise exception.BackupDriverException(reason=msg)
 
         self.conn = discovery.build('storage',
diff --git a/cinder/tests/unit/backup/drivers/test_backup_google.py b/cinder/tests/unit/backup/drivers/test_backup_google.py
index 66d23cbf5fb..504b84f35f3 100644
--- a/cinder/tests/unit/backup/drivers/test_backup_google.py
+++ b/cinder/tests/unit/backup/drivers/test_backup_google.py
@@ -66,8 +66,6 @@ class FakeObjectName(object):
 
 
 def gcs_client(func):
-    @mock.patch.object(google_dr.client, 'GoogleCredentials',
-                       fake_google_client.FakeGoogleCredentials)
     @mock.patch.object(google_dr.discovery, 'build',
                        fake_google_client.FakeGoogleDiscovery.Build)
     @mock.patch.object(google_dr, 'GoogleMediaIoBaseDownload',
@@ -85,8 +83,6 @@ def gcs_client(func):
 
 
 def gcs_client2(func):
-    @mock.patch.object(google_dr.client, 'GoogleCredentials',
-                       fake_google_client2.FakeGoogleCredentials)
     @mock.patch.object(google_dr.discovery, 'build',
                        fake_google_client2.FakeGoogleDiscovery.Build)
     @mock.patch.object(google_dr, 'GoogleMediaIoBaseDownload',
@@ -635,34 +631,15 @@ class GoogleBackupDriverTestCase(test.TestCase):
         self.assertEqual('none', result[0])
         self.assertEqual(already_compressed_data, result[1])
 
-    @mock.patch.object(google_dr.client.GoogleCredentials, 'from_stream')
-    @mock.patch.object(google_dr.discovery, 'build')
-    @mock.patch.object(google_dr, 'service_account', None)
-    def test_no_httplib2_auth(self, build, from_stream):
-        # Google api client requires google-auth-httplib2 if not present we
-        # use legacy credentials
-        google_dr.CONF.set_override('backup_gcs_credential_file',
-                                    'credentials_file')
-
-        google_dr.GoogleBackupDriver(self.ctxt)
-
-        from_stream.assert_called_once_with('credentials_file')
-        build.assert_called_once_with('storage', 'v1', cache_discovery=False,
-                                      credentials=from_stream.return_value)
-
     @mock.patch.object(google_dr, 'gexceptions', mock.Mock())
-    @mock.patch.object(google_dr.client.GoogleCredentials, 'from_stream')
     @mock.patch.object(google_dr.discovery, 'build')
     @mock.patch.object(google_dr, 'service_account')
-    def test_google_auth_used(self, account, build, from_stream):
-        # Google api client requires google-auth-httplib2 if not present we
-        # use legacy credentials
+    def test_client_setup(self, account, build):
         google_dr.CONF.set_override('backup_gcs_credential_file',
                                     'credentials_file')
 
         google_dr.GoogleBackupDriver(self.ctxt)
 
-        from_stream.assert_not_called()
         create_creds = account.Credentials.from_service_account_file
         create_creds.assert_called_once_with('credentials_file')
         build.assert_called_once_with('storage', 'v1', cache_discovery=False,
diff --git a/cinder/tests/unit/backup/fake_google_client.py b/cinder/tests/unit/backup/fake_google_client.py
index 5d3c294095b..58ee8371861 100644
--- a/cinder/tests/unit/backup/fake_google_client.py
+++ b/cinder/tests/unit/backup/fake_google_client.py
@@ -18,8 +18,8 @@ import json
 import os
 import zlib
 
+from google.auth import exceptions as gexceptions
 from googleapiclient import errors
-from oauth2client import client
 from oslo_utils import units
 
 
@@ -55,7 +55,7 @@ class FakeGoogleBucketListExecute(object):
 
     def execute(self, *args, **kwargs):
         if self.container_name == 'gcs_oauth2_failure':
-            raise client.Error
+            raise gexceptions.DefaultCredentialsError
         return {u'items': [{u'name': u'gcscinderbucket'},
                            {u'name': u'gcsbucket'}]}
 
diff --git a/requirements.txt b/requirements.txt
index 44a810f578b..2e342031fa1 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -12,7 +12,6 @@ jsonschema>=3.2.0 # MIT
 keystoneauth1>=4.2.1 # Apache-2.0
 keystonemiddleware>=9.1.0 # Apache-2.0
 lxml>=4.5.2 # BSD
-oauth2client>=4.1.3 # Apache-2.0
 oslo.config>=8.3.2 # Apache-2.0
 oslo.concurrency>=4.5.0 # Apache-2.0
 oslo.context>=3.4.0 # Apache-2.0