diff --git a/lower-constraints.txt b/lower-constraints.txt
index 10113d07..c4474b66 100644
--- a/lower-constraints.txt
+++ b/lower-constraints.txt
@@ -27,9 +27,7 @@ kombu==4.1.0
 linecache2==1.0.0
 MarkupSafe==1.0
 mccabe==0.2.1
-mock==2.0.0
 monotonic==1.4
-mox3==0.20.0
 msgpack-python==0.4.0
 msgpack==0.5.6
 netaddr==0.7.18
diff --git a/os_vif/tests/unit/internal/ip/linux/test_impl_pyroute2.py b/os_vif/tests/unit/internal/ip/linux/test_impl_pyroute2.py
index 603afaca..2338630a 100644
--- a/os_vif/tests/unit/internal/ip/linux/test_impl_pyroute2.py
+++ b/os_vif/tests/unit/internal/ip/linux/test_impl_pyroute2.py
@@ -10,7 +10,8 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-import mock
+from unittest import mock
+
 from pyroute2 import iproute
 from pyroute2.netlink import exceptions as ipexc
 from pyroute2.netlink.rtnl import ifinfmsg
diff --git a/os_vif/tests/unit/internal/ip/test_api.py b/os_vif/tests/unit/internal/ip/test_api.py
index 30bad184..6bc43350 100644
--- a/os_vif/tests/unit/internal/ip/test_api.py
+++ b/os_vif/tests/unit/internal/ip/test_api.py
@@ -12,7 +12,7 @@
 
 import importlib
 
-import mock
+from unittest import mock
 
 from os_vif.internal.ip import api
 from os_vif.tests.unit import base
diff --git a/os_vif/tests/unit/internal/ip/windows/test_impl_netifaces.py b/os_vif/tests/unit/internal/ip/windows/test_impl_netifaces.py
index cb115c84..fc88149c 100644
--- a/os_vif/tests/unit/internal/ip/windows/test_impl_netifaces.py
+++ b/os_vif/tests/unit/internal/ip/windows/test_impl_netifaces.py
@@ -10,7 +10,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import mock
+from unittest import mock
+
 import netifaces
 
 from os_vif.internal.ip.windows import impl_netifaces as ip_lib
diff --git a/os_vif/tests/unit/test_base.py b/os_vif/tests/unit/test_base.py
index 95be63c0..0c343506 100644
--- a/os_vif/tests/unit/test_base.py
+++ b/os_vif/tests/unit/test_base.py
@@ -11,7 +11,8 @@
 # under the License.
 
 import copy
-import mock
+
+from unittest import mock
 
 from oslo_serialization import jsonutils
 from oslo_versionedobjects import base
diff --git a/os_vif/tests/unit/test_os_vif.py b/os_vif/tests/unit/test_os_vif.py
index 91c2e272..6ec20562 100644
--- a/os_vif/tests/unit/test_os_vif.py
+++ b/os_vif/tests/unit/test_os_vif.py
@@ -10,7 +10,8 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-import mock
+from unittest import mock
+
 from oslo_config import cfg
 from stevedore import extension
 
diff --git a/vif_plug_linux_bridge/tests/unit/test_linux_net.py b/vif_plug_linux_bridge/tests/unit/test_linux_net.py
index c57f8187..51cb7cfc 100644
--- a/vif_plug_linux_bridge/tests/unit/test_linux_net.py
+++ b/vif_plug_linux_bridge/tests/unit/test_linux_net.py
@@ -10,17 +10,19 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-import mock
-import testtools
+from unittest import mock
 
 import fixtures
-from os_vif.internal.ip.api import ip as ip_lib
+import testtools
+
 from oslo_concurrency import lockutils
 from oslo_concurrency import processutils
 from oslo_config import cfg
 from oslo_config import fixture as config_fixture
 from oslo_log.fixture import logging_error as log_fixture
 
+from os_vif.internal.ip.api import ip as ip_lib
+
 from vif_plug_linux_bridge import linux_net
 from vif_plug_linux_bridge import privsep
 
diff --git a/vif_plug_linux_bridge/tests/unit/test_plugin.py b/vif_plug_linux_bridge/tests/unit/test_plugin.py
index f3db356d..ea6c3c9a 100644
--- a/vif_plug_linux_bridge/tests/unit/test_plugin.py
+++ b/vif_plug_linux_bridge/tests/unit/test_plugin.py
@@ -10,7 +10,8 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-import mock
+from unittest import mock
+
 import testtools
 
 from os_vif import objects
diff --git a/vif_plug_ovs/tests/functional/ovsdb/test_ovsdb_lib.py b/vif_plug_ovs/tests/functional/ovsdb/test_ovsdb_lib.py
index ccbea725..e1acb28f 100644
--- a/vif_plug_ovs/tests/functional/ovsdb/test_ovsdb_lib.py
+++ b/vif_plug_ovs/tests/functional/ovsdb/test_ovsdb_lib.py
@@ -10,14 +10,16 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-import mock
 import random
 
+from unittest import mock
+
+import testscenarios
+
 from oslo_concurrency import processutils
 from oslo_config import cfg
 from oslo_utils import uuidutils
 from ovsdbapp.schema.open_vswitch import impl_idl
-import testscenarios
 
 from vif_plug_ovs import constants
 from vif_plug_ovs import linux_net
diff --git a/vif_plug_ovs/tests/unit/ovsdb/test_ovsdb_lib.py b/vif_plug_ovs/tests/unit/ovsdb/test_ovsdb_lib.py
index 619e2dee..899f7cd8 100644
--- a/vif_plug_ovs/tests/unit/ovsdb/test_ovsdb_lib.py
+++ b/vif_plug_ovs/tests/unit/ovsdb/test_ovsdb_lib.py
@@ -10,7 +10,8 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-import mock
+from unittest import mock
+
 import testtools
 
 from oslo_concurrency import processutils
diff --git a/vif_plug_ovs/tests/unit/test_linux_net.py b/vif_plug_ovs/tests/unit/test_linux_net.py
index f96eba55..659b1a22 100644
--- a/vif_plug_ovs/tests/unit/test_linux_net.py
+++ b/vif_plug_ovs/tests/unit/test_linux_net.py
@@ -11,8 +11,10 @@
 # under the License.
 
 import glob
-import mock
 import os.path
+
+from unittest import mock
+
 import testtools
 
 from os_vif.internal.ip.api import ip as ip_lib
diff --git a/vif_plug_ovs/tests/unit/test_plugin.py b/vif_plug_ovs/tests/unit/test_plugin.py
index 64f0d73a..212dc9f7 100644
--- a/vif_plug_ovs/tests/unit/test_plugin.py
+++ b/vif_plug_ovs/tests/unit/test_plugin.py
@@ -10,7 +10,8 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-import mock
+from unittest import mock
+
 import testtools
 
 from os_vif.internal.ip.api import ip as ip_lib