diff --git a/lower-constraints.txt b/lower-constraints.txt
index e4c72a1..1495402 100644
--- a/lower-constraints.txt
+++ b/lower-constraints.txt
@@ -15,7 +15,6 @@ keystoneauth1==3.4.0
 linecache2==1.0.0
 MarkupSafe==1.0
 mccabe==0.2.1
-mock==2.0.0
 netaddr==0.7.18
 openstackdocstheme==1.18.1
 oslo.config==5.2.0
diff --git a/oslotest/base.py b/oslotest/base.py
index fb4b02d..acb7a33 100644
--- a/oslotest/base.py
+++ b/oslotest/base.py
@@ -16,6 +16,7 @@
 """Common utilities used in testing"""
 
 import logging
+from unittest import mock
 
 import fixtures
 from oslotest import createfile
@@ -23,7 +24,6 @@ from oslotest import log
 from oslotest import output
 from oslotest import timeout
 
-from six.moves import mock
 import testtools
 
 LOG = logging.getLogger(__name__)
diff --git a/oslotest/mock_fixture.py b/oslotest/mock_fixture.py
index 506cfbd..4e3deab 100644
--- a/oslotest/mock_fixture.py
+++ b/oslotest/mock_fixture.py
@@ -15,9 +15,9 @@
 #    under the License.
 
 import functools
+from unittest import mock
 
 import fixtures
-import mock
 
 
 def _lazy_autospec_method(mocked_method, original_method, eat_self):
@@ -72,8 +72,10 @@ class _AutospecMockMixin(object):
         original_attr = getattr(original_spec, name)
         if callable(original_attr):
             # lazily autospec callable attribute.
-            eat_self = mock.mock._must_skip(original_spec, name,
-                                            isinstance(original_spec, type))
+            eat_self = mock._must_skip(
+                original_spec, name,
+                isinstance(original_spec, type)
+            )
 
             _lazy_autospec_method(attr, original_attr, eat_self)
 
@@ -110,15 +112,17 @@ class MockAutospecFixture(fixtures.Fixture):
         super(MockAutospecFixture, self).setUp()
 
         # patch both external and internal usage of Mock / MagicMock.
-        self.useFixture(fixtures.MonkeyPatch('mock.Mock', _AutospecMock))
-        self.useFixture(fixtures.MonkeyPatch('mock.mock.Mock', _AutospecMock))
-        self.useFixture(fixtures.MonkeyPatch('mock.MagicMock',
-                                             _AutospecMagicMock))
-        self.useFixture(fixtures.MonkeyPatch('mock.mock.MagicMock',
-                                             _AutospecMagicMock))
+        self.useFixture(
+            fixtures.MonkeyPatch(
+                'unittest.mock.Mock',
+                _AutospecMock))
+        self.useFixture(
+            fixtures.MonkeyPatch(
+                'unittest.mock.MagicMock',
+                _AutospecMagicMock))
 
 
-class _patch(mock.mock._patch):
+class _patch(mock._patch):
     """Patch class with working autospec functionality.
 
     Currently, mock.patch functionality doesn't handle the autospec parameter
@@ -159,8 +163,11 @@ class _patch(mock.mock._patch):
         if autospec:
             target = self.getter()
             original_attr = getattr(target, self.attribute)
-            eat_self = mock.mock._must_skip(target, self.attribute,
-                                            isinstance(target, type))
+            eat_self = mock._must_skip(
+                target,
+                self.attribute,
+                isinstance(target, type)
+            )
 
             new = super(_patch, self).__enter__()
 
@@ -186,11 +193,11 @@ def _safe_attribute_error_wrapper(func):
 
 def patch_mock_module():
     """Replaces the mock.patch class."""
-    mock.mock._patch = _patch
+    mock._patch = _patch
 
     # NOTE(claudiub): mock cannot autospec partial functions properly,
     # especially those created by LazyLoader objects (scheduler client),
     # as it will try to copy the partial function's __name__ (which they do
     # not have).
-    mock.mock._copy_func_details = _safe_attribute_error_wrapper(
-        mock.mock._copy_func_details)
+    mock._copy_func_details = _safe_attribute_error_wrapper(
+        mock._copy_func_details)
diff --git a/oslotest/tests/unit/test_base.py b/oslotest/tests/unit/test_base.py
index b98c672..86e76d4 100644
--- a/oslotest/tests/unit/test_base.py
+++ b/oslotest/tests/unit/test_base.py
@@ -17,10 +17,10 @@
 import logging
 import os
 import unittest
+from unittest import mock
 
 import fixtures
 import six
-from six.moves import mock
 import testtools
 
 from oslotest import base
diff --git a/oslotest/tests/unit/test_log.py b/oslotest/tests/unit/test_log.py
index 55c02a0..f5fdc49 100644
--- a/oslotest/tests/unit/test_log.py
+++ b/oslotest/tests/unit/test_log.py
@@ -15,8 +15,8 @@
 #    under the License.
 
 import logging
+from unittest import mock
 
-from six.moves import mock
 import testtools
 
 from oslotest import log
diff --git a/oslotest/tests/unit/test_mock_fixture.py b/oslotest/tests/unit/test_mock_fixture.py
index e578fb4..896bbcb 100644
--- a/oslotest/tests/unit/test_mock_fixture.py
+++ b/oslotest/tests/unit/test_mock_fixture.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 oslotest import mock_fixture
 
diff --git a/oslotest/tests/unit/test_output.py b/oslotest/tests/unit/test_output.py
index b4abcf0..1f67ba8 100644
--- a/oslotest/tests/unit/test_output.py
+++ b/oslotest/tests/unit/test_output.py
@@ -13,12 +13,12 @@
 #    under the License.
 
 import sys
+from unittest import mock
+
+import testtools
 
 from oslotest import output
 
-from six.moves import mock
-import testtools
-
 
 class CaptureOutputTest(testtools.TestCase):
 
diff --git a/oslotest/tests/unit/test_timeout.py b/oslotest/tests/unit/test_timeout.py
index 38c7a3d..9c0b32c 100644
--- a/oslotest/tests/unit/test_timeout.py
+++ b/oslotest/tests/unit/test_timeout.py
@@ -12,7 +12,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-from six.moves import mock
+from unittest import mock
+
 import testtools
 
 from oslotest import timeout
diff --git a/requirements.txt b/requirements.txt
index 9826c3b..32baed1 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -6,4 +6,3 @@ fixtures>=3.0.0 # Apache-2.0/BSD
 python-subunit>=1.0.0 # Apache-2.0/BSD
 six>=1.10.0 # MIT
 testtools>=2.2.0 # MIT
-mock>=2.0.0 # BSD