diff --git a/tests/unit/test_flow.py b/tests/unit/test_flow.py
index 73cd569..65ced12 100644
--- a/tests/unit/test_flow.py
+++ b/tests/unit/test_flow.py
@@ -19,8 +19,8 @@
 import os
 import re
 import socket
+from unittest import mock
 
-import mock
 import pytest
 import requests
 import urllib
diff --git a/tests/unit/test_helpers.py b/tests/unit/test_helpers.py
index 9df49de..2aa2269 100644
--- a/tests/unit/test_helpers.py
+++ b/tests/unit/test_helpers.py
@@ -15,8 +15,8 @@
 import datetime
 import json
 import os
+from unittest import mock
 
-import mock
 import pytest
 
 from google.auth import external_account_authorized_user
diff --git a/tests/unit/test_interactive.py b/tests/unit/test_interactive.py
index 3a354eb..88a5bf9 100644
--- a/tests/unit/test_interactive.py
+++ b/tests/unit/test_interactive.py
@@ -13,8 +13,8 @@
 # limitations under the License.
 
 import socket
+from unittest import mock
 
-import mock
 import pytest
 
 
diff --git a/tests/unit/test_tool.py b/tests/unit/test_tool.py
index d76ee53..dd4fd48 100644
--- a/tests/unit/test_tool.py
+++ b/tests/unit/test_tool.py
@@ -16,10 +16,10 @@
 import json
 import os.path
 import tempfile
+from unittest import mock
 
 import click.testing
 import google.oauth2.credentials
-import mock
 import pytest
 
 import google_auth_oauthlib.flow