diff --git a/tackerclient/tests/unit/osc/base.py b/tackerclient/tests/unit/osc/base.py
index 3037ed80..4e7d3d33 100644
--- a/tackerclient/tests/unit/osc/base.py
+++ b/tackerclient/tests/unit/osc/base.py
@@ -13,9 +13,9 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import mock
 from requests_mock.contrib import fixture as requests_mock_fixture
 import testtools
+from unittest import mock
 
 from cliff import columns as cliff_columns
 
diff --git a/tackerclient/tests/unit/osc/v1/test_vnf_package.py b/tackerclient/tests/unit/osc/v1/test_vnf_package.py
index cff4a2fe..2aff1e51 100644
--- a/tackerclient/tests/unit/osc/v1/test_vnf_package.py
+++ b/tackerclient/tests/unit/osc/v1/test_vnf_package.py
@@ -18,9 +18,9 @@ import os
 import shutil
 import sys
 import tempfile
+from unittest import mock
 
 import ddt
-import mock
 import zipfile
 
 from tackerclient.common import exceptions
diff --git a/tackerclient/tests/unit/osc/v1/test_vnflcm.py b/tackerclient/tests/unit/osc/v1/test_vnflcm.py
index f45ab6ce..da5ea6b4 100644
--- a/tackerclient/tests/unit/osc/v1/test_vnflcm.py
+++ b/tackerclient/tests/unit/osc/v1/test_vnflcm.py
@@ -16,9 +16,9 @@
 from io import StringIO
 import os
 import sys
+from unittest import mock
 
 import ddt
-import mock
 from oslo_utils.fixture import uuidsentinel
 import six
 
diff --git a/tackerclient/tests/unit/osc/v1/vnf/test_vnf.py b/tackerclient/tests/unit/osc/v1/vnf/test_vnf.py
index 599b24b0..7d8060da 100644
--- a/tackerclient/tests/unit/osc/v1/vnf/test_vnf.py
+++ b/tackerclient/tests/unit/osc/v1/vnf/test_vnf.py
@@ -15,8 +15,9 @@
 #    under the License.
 
 import ast
+from unittest import mock
+
 import fixtures
-import mock
 import yaml
 
 from tackerclient.common import exceptions
diff --git a/tackerclient/tests/unit/test_auth.py b/tackerclient/tests/unit/test_auth.py
index 3dea71b9..3da14406 100644
--- a/tackerclient/tests/unit/test_auth.py
+++ b/tackerclient/tests/unit/test_auth.py
@@ -16,10 +16,10 @@
 
 import copy
 import json
+from unittest import mock
 import uuid
 
 from keystoneclient import exceptions as k_exceptions
-import mock
 import requests
 import testtools
 
diff --git a/tackerclient/tests/unit/test_cli10.py b/tackerclient/tests/unit/test_cli10.py
index 56776ec5..0ae3f978 100644
--- a/tackerclient/tests/unit/test_cli10.py
+++ b/tackerclient/tests/unit/test_cli10.py
@@ -14,11 +14,11 @@
 #    under the License.
 #
 
+from unittest import mock
 import urllib
 
 import contextlib
 import fixtures
-import mock
 import six
 import six.moves.urllib.parse as urlparse
 import sys
diff --git a/tackerclient/tests/unit/test_http.py b/tackerclient/tests/unit/test_http.py
index 196eee44..9244428f 100644
--- a/tackerclient/tests/unit/test_http.py
+++ b/tackerclient/tests/unit/test_http.py
@@ -13,8 +13,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import mock
 import testtools
+from unittest import mock
 
 from tackerclient.client import HTTPClient
 from tackerclient.common import exceptions
diff --git a/tackerclient/tests/unit/test_shell.py b/tackerclient/tests/unit/test_shell.py
index ab9bd995..f7dec351 100644
--- a/tackerclient/tests/unit/test_shell.py
+++ b/tackerclient/tests/unit/test_shell.py
@@ -17,12 +17,13 @@ import argparse
 import logging
 import os
 import re
+from unittest import mock
+
 import six
 import sys
 
 import fixtures
 from keystoneclient import session
-import mock
 import testtools
 from testtools import matchers
 
diff --git a/tackerclient/tests/unit/test_ssl.py b/tackerclient/tests/unit/test_ssl.py
index b9b278bc..1ce4c7d7 100644
--- a/tackerclient/tests/unit/test_ssl.py
+++ b/tackerclient/tests/unit/test_ssl.py
@@ -13,9 +13,10 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from unittest import mock
+
 import fixtures
 from keystoneclient import session
-import mock
 import requests
 import testtools
 
diff --git a/tackerclient/tests/unit/vm/test_cli10_vnf.py b/tackerclient/tests/unit/vm/test_cli10_vnf.py
index 252ed9b6..70965733 100644
--- a/tackerclient/tests/unit/vm/test_cli10_vnf.py
+++ b/tackerclient/tests/unit/vm/test_cli10_vnf.py
@@ -13,8 +13,8 @@
 #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 #    License for the specific language governing permissions and limitations
 #    under the License.
-import mock
 import sys
+from unittest import mock
 
 from tackerclient.common import exceptions
 from tackerclient.common import utils
diff --git a/tackerclient/tests/unit/vm/test_cli10_vnfd.py b/tackerclient/tests/unit/vm/test_cli10_vnfd.py
index 491e7b35..25a26aeb 100644
--- a/tackerclient/tests/unit/vm/test_cli10_vnfd.py
+++ b/tackerclient/tests/unit/vm/test_cli10_vnfd.py
@@ -14,13 +14,13 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from mock import mock_open
-from mock import patch
 import sys
 
 from tackerclient.common.exceptions import InvalidInput
 from tackerclient.tacker.v1_0.vnfm import vnfd
 from tackerclient.tests.unit import test_cli10
+from unittest.mock import mock_open
+from unittest.mock import patch
 
 
 class CLITestV10VmVNFDJSON(test_cli10.CLITestV10Base):
diff --git a/tackerclient/tests/unit/vm/test_cli10_vnffgd.py b/tackerclient/tests/unit/vm/test_cli10_vnffgd.py
index 652e9b61..51ad6a89 100644
--- a/tackerclient/tests/unit/vm/test_cli10_vnffgd.py
+++ b/tackerclient/tests/unit/vm/test_cli10_vnffgd.py
@@ -10,12 +10,12 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-from mock import mock_open
-from mock import patch
 import sys
 
 from tackerclient.tacker.v1_0.nfvo import vnffgd
 from tackerclient.tests.unit import test_cli10
+from unittest.mock import mock_open
+from unittest.mock import patch
 
 
 class CLITestV10VmVNFFGDJSON(test_cli10.CLITestV10Base):
diff --git a/tackerclient/tests/unit/vm/test_vim_utils.py b/tackerclient/tests/unit/vm/test_vim_utils.py
index 3f0df3f5..e88295e3 100644
--- a/tackerclient/tests/unit/vm/test_vim_utils.py
+++ b/tackerclient/tests/unit/vm/test_vim_utils.py
@@ -13,12 +13,11 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-
-from mock import sentinel
 import testtools
 
 from tackerclient.common import exceptions
 from tackerclient.tacker.v1_0.nfvo import vim_utils
+from unittest.mock import sentinel
 
 
 class TestVIMUtils(testtools.TestCase):
diff --git a/test-requirements.txt b/test-requirements.txt
index 2558a1ea..9a4ff192 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -10,4 +10,3 @@ python-subunit>=1.0.0 # Apache-2.0/BSD
 requests-mock>=1.2.0 # Apache-2.0
 stestr>=2.0.0 # Apache-2.0
 testtools>=2.2.0 # MIT
-mock>=2.0.0 # BSD