diff --git a/noxfile.py b/noxfile.py
index 2e2e03abc3a..fda6416526f 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -42,7 +42,6 @@
     "pytest-cov",
     "webtest",
     "coverage",
-    "mock",
 ]
 
 
diff --git a/tests/test__auth.py b/tests/test__auth.py
index 6809647b785..8b6b5624032 100644
--- a/tests/test__auth.py
+++ b/tests/test__auth.py
@@ -13,11 +13,11 @@
 # limitations under the License.
 
 import unittest
+from unittest import mock
 
 import google.auth.credentials
 import google_auth_httplib2
 import httplib2
-import mock
 import oauth2client.client
 
 from googleapiclient import _auth
diff --git a/tests/test__helpers.py b/tests/test__helpers.py
index 51e5c595260..56df6f88079 100644
--- a/tests/test__helpers.py
+++ b/tests/test__helpers.py
@@ -15,10 +15,9 @@
 """Unit tests for googleapiclient._helpers."""
 
 import unittest
+from unittest import mock
 import urllib
 
-import mock
-
 from googleapiclient import _helpers
 
 
diff --git a/tests/test_discovery.py b/tests/test_discovery.py
index 36a0d524f26..8f4bdec1f03 100644
--- a/tests/test_discovery.py
+++ b/tests/test_discovery.py
@@ -35,6 +35,7 @@
 import re
 import sys
 import unittest
+from unittest import mock
 import urllib
 
 import google.api_core.exceptions
@@ -42,7 +43,6 @@
 from google.auth.exceptions import MutualTLSChannelError
 import google_auth_httplib2
 import httplib2
-import mock
 from oauth2client import GOOGLE_TOKEN_URI
 from oauth2client.client import GoogleCredentials, OAuth2Credentials
 from parameterized import parameterized
diff --git a/tests/test_discovery_cache.py b/tests/test_discovery_cache.py
index d9b43470b27..678350505d6 100644
--- a/tests/test_discovery_cache.py
+++ b/tests/test_discovery_cache.py
@@ -19,8 +19,7 @@
 
 import datetime
 import unittest
-
-import mock
+from unittest import mock
 
 from googleapiclient.discovery_cache import DISCOVERY_DOC_MAX_AGE
 
diff --git a/tests/test_http.py b/tests/test_http.py
index 3233f668ce7..e7b57dfaff3 100644
--- a/tests/test_http.py
+++ b/tests/test_http.py
@@ -34,10 +34,10 @@
 import ssl
 import time
 import unittest
+from unittest import mock
 import urllib
 
 import httplib2
-import mock
 from oauth2client.client import Credentials
 
 from googleapiclient.discovery import build