diff --git a/lower-constraints.txt b/lower-constraints.txt
index bfadfcb0..2bd229a2 100644
--- a/lower-constraints.txt
+++ b/lower-constraints.txt
@@ -22,7 +22,6 @@ linecache2==1.0.0
 lxml==3.4.1
 MarkupSafe==1.0
 mccabe==0.2.1
-mock==2.0.0
 netaddr==0.7.18
 netifaces==0.10.4
 openstackdocstheme==1.20.0
diff --git a/oslo_vmware/tests/objects/test_datacenter.py b/oslo_vmware/tests/objects/test_datacenter.py
index c4d261ed..2a346f97 100644
--- a/oslo_vmware/tests/objects/test_datacenter.py
+++ b/oslo_vmware/tests/objects/test_datacenter.py
@@ -12,7 +12,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import mock
+from unittest import mock
 
 from oslo_vmware.objects import datacenter
 from oslo_vmware.tests import base
diff --git a/oslo_vmware/tests/objects/test_datastore.py b/oslo_vmware/tests/objects/test_datastore.py
index bda052b4..68cc0ead 100644
--- a/oslo_vmware/tests/objects/test_datastore.py
+++ b/oslo_vmware/tests/objects/test_datastore.py
@@ -12,7 +12,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import mock
+from unittest import mock
+
 from oslo_utils import units
 import urllib.parse as urlparse
 
diff --git a/oslo_vmware/tests/test_api.py b/oslo_vmware/tests/test_api.py
index 298aabd8..499436d7 100644
--- a/oslo_vmware/tests/test_api.py
+++ b/oslo_vmware/tests/test_api.py
@@ -14,16 +14,15 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-"""
-Unit tests for session management and API invocation classes.
-"""
+"""Unit tests for session management and API invocation classes."""
 
 from datetime import datetime
+from unittest import mock
+
 from eventlet import greenthread
-import mock
+from oslo_context import context
 import suds
 
-from oslo_context import context
 from oslo_vmware import api
 from oslo_vmware import exceptions
 from oslo_vmware import pbm
diff --git a/oslo_vmware/tests/test_dvs_util.py b/oslo_vmware/tests/test_dvs_util.py
index 1179d46f..8382a401 100644
--- a/oslo_vmware/tests/test_dvs_util.py
+++ b/oslo_vmware/tests/test_dvs_util.py
@@ -13,13 +13,10 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-"""
-Unit tests for VMware DVS utility module.
-"""
+"""Unit tests for VMware DVS utility module."""
 
 import collections
-
-import mock
+from unittest import mock
 
 from oslo_vmware import dvs_util
 from oslo_vmware.tests import base
diff --git a/oslo_vmware/tests/test_exceptions.py b/oslo_vmware/tests/test_exceptions.py
index d70756bd..6c393ad2 100644
--- a/oslo_vmware/tests/test_exceptions.py
+++ b/oslo_vmware/tests/test_exceptions.py
@@ -13,10 +13,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-"""
-Unit tests for exceptions module.
-"""
-import mock
+"""Unit tests for exceptions module."""
+from unittest import mock
 
 from oslo_vmware._i18n import _
 from oslo_vmware import exceptions
diff --git a/oslo_vmware/tests/test_image_transfer.py b/oslo_vmware/tests/test_image_transfer.py
index f1ad58b3..b21bedb1 100644
--- a/oslo_vmware/tests/test_image_transfer.py
+++ b/oslo_vmware/tests/test_image_transfer.py
@@ -13,13 +13,10 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-"""
-Unit tests for functions and classes for image transfer.
-"""
+"""Unit tests for functions and classes for image transfer."""
 
 import io
-
-import mock
+from unittest import mock
 
 from oslo_vmware import exceptions
 from oslo_vmware import image_transfer
diff --git a/oslo_vmware/tests/test_pbm.py b/oslo_vmware/tests/test_pbm.py
index 3b57506c..2a3b29f6 100644
--- a/oslo_vmware/tests/test_pbm.py
+++ b/oslo_vmware/tests/test_pbm.py
@@ -13,13 +13,11 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-"""
-Unit tests for PBM utility methods.
-"""
+"""Unit tests for PBM utility methods."""
 
 import os
+from unittest import mock
 
-import mock
 import urllib.parse as urlparse
 import urllib.request as urllib
 
diff --git a/oslo_vmware/tests/test_rw_handles.py b/oslo_vmware/tests/test_rw_handles.py
index b35faed9..1301bb78 100644
--- a/oslo_vmware/tests/test_rw_handles.py
+++ b/oslo_vmware/tests/test_rw_handles.py
@@ -13,13 +13,11 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-"""
-Unit tests for read and write handles for image transfer.
-"""
+"""Unit tests for read and write handles for image transfer."""
 
 import ssl
+from unittest import mock
 
-import mock
 import requests
 
 from oslo_vmware import exceptions
diff --git a/oslo_vmware/tests/test_service.py b/oslo_vmware/tests/test_service.py
index 20654542..c3cc23f1 100644
--- a/oslo_vmware/tests/test_service.py
+++ b/oslo_vmware/tests/test_service.py
@@ -15,9 +15,9 @@
 
 import http.client as httplib
 import io
+from unittest import mock
 
 import ddt
-import mock
 import requests
 import suds
 
diff --git a/oslo_vmware/tests/test_vim.py b/oslo_vmware/tests/test_vim.py
index ddfa82eb..0887a05a 100644
--- a/oslo_vmware/tests/test_vim.py
+++ b/oslo_vmware/tests/test_vim.py
@@ -13,13 +13,11 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-"""
-Unit tests for classes to invoke VMware VI SOAP calls.
-"""
+"""Unit tests for classes to invoke VMware VI SOAP calls."""
 
 import copy
+from unittest import mock
 
-import mock
 from oslo_i18n import fixture as i18n_fixture
 import suds
 
diff --git a/oslo_vmware/tests/test_vim_util.py b/oslo_vmware/tests/test_vim_util.py
index 36d63751..e73bf6e3 100644
--- a/oslo_vmware/tests/test_vim_util.py
+++ b/oslo_vmware/tests/test_vim_util.py
@@ -13,13 +13,10 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-"""
-Unit tests for VMware API utility module.
-"""
+"""Unit tests for VMware API utility module."""
 
 import collections
-
-import mock
+from unittest import mock
 
 from oslo_vmware.tests import base
 from oslo_vmware import vim_util
diff --git a/test-requirements.txt b/test-requirements.txt
index 3c8beeb2..65fa4f8f 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -6,7 +6,6 @@
 hacking>=3.0,<3.1.0 # Apache-2.0
 
 fixtures>=3.0.0 # Apache-2.0/BSD
-mock>=2.0.0 # BSD
 testtools>=2.2.0 # MIT
 stestr>=2.0.0 # Apache-2.0