diff --git a/test-requirements.txt b/test-requirements.txt
index e6fd2ab6..a85f92ec 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -12,7 +12,6 @@ python-subunit>=0.0.18
 oslotest>=1.2.0  # Apache-2.0
 stestr>=2.0.0 # Apache-2.0
 testscenarios>=0.4
-mock>=2.0 # BSD
 testtools>=0.9.36,!=1.2.0
 python-swiftclient>=3.1.0
 python-keystoneclient
diff --git a/tests/unit/agent/common/test_server.py b/tests/unit/agent/common/test_server.py
index b54ba2c1..81993d1a 100644
--- a/tests/unit/agent/common/test_server.py
+++ b/tests/unit/agent/common/test_server.py
@@ -12,9 +12,9 @@
 # implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import mock
 import json
 import unittest
+from unittest import mock
 
 from storlets.sbus import command as sbus_cmd
 from storlets.sbus.file_description import SBUS_FD_SERVICE_OUT
diff --git a/tests/unit/agent/daemon/test_server.py b/tests/unit/agent/daemon/test_server.py
index 43d9d5b9..4ecd82fa 100644
--- a/tests/unit/agent/daemon/test_server.py
+++ b/tests/unit/agent/daemon/test_server.py
@@ -12,8 +12,8 @@
 # implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import mock
 import unittest
+from unittest import mock
 
 from storlets.sbus import command as sbus_cmd
 from storlets.agent.daemon.server import StorletDaemon, StorletDaemonLoadError
diff --git a/tests/unit/agent/daemon_factory/test_server.py b/tests/unit/agent/daemon_factory/test_server.py
index 873cd1f3..ad1f780a 100644
--- a/tests/unit/agent/daemon_factory/test_server.py
+++ b/tests/unit/agent/daemon_factory/test_server.py
@@ -14,8 +14,8 @@
 # limitations under the License.
 from contextlib import contextmanager
 import errno
-import mock
 import unittest
+from unittest import mock
 
 from storlets.sbus import command as sbus_cmd
 from storlets.sbus.client import SBusResponse
diff --git a/tests/unit/gateway/common/test_stob.py b/tests/unit/gateway/common/test_stob.py
index ac5d5080..189ca89a 100644
--- a/tests/unit/gateway/common/test_stob.py
+++ b/tests/unit/gateway/common/test_stob.py
@@ -14,10 +14,11 @@
 # limitations under the License.
 
 from contextlib import contextmanager
-import mock
 import os
 import tempfile
 import unittest
+from unittest import mock
+
 from storlets.gateway.common.stob import FileDescriptorIterator
 
 
diff --git a/tests/unit/gateway/gateways/docker/test_gateway.py b/tests/unit/gateway/gateways/docker/test_gateway.py
index d187d707..a5fbb98f 100644
--- a/tests/unit/gateway/gateways/docker/test_gateway.py
+++ b/tests/unit/gateway/gateways/docker/test_gateway.py
@@ -13,16 +13,15 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import eventlet
+from io import BytesIO, StringIO
+import json
 import os
 import os.path
 from shutil import rmtree
 from tempfile import mkdtemp
-import eventlet
-import json
-from io import BytesIO, StringIO
-
-import mock
 import unittest
+from unittest import mock
 
 from swift.common.swob import Request, Response
 from swift.common.utils import FileLikeIter
diff --git a/tests/unit/gateway/gateways/docker/test_runtime.py b/tests/unit/gateway/gateways/docker/test_runtime.py
index c2dc0436..d55b1686 100644
--- a/tests/unit/gateway/gateways/docker/test_runtime.py
+++ b/tests/unit/gateway/gateways/docker/test_runtime.py
@@ -13,19 +13,19 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import mock
-import os
-import unittest
-import tempfile
-import errno
 from contextlib import contextmanager
+import errno
 from io import StringIO
+import os
 from stat import ST_MODE
+import tempfile
+import unittest
+from unittest import mock
+
 import docker.client
 import docker.errors
 import docker.models.containers
 
-
 from storlets.sbus.client import SBusResponse
 from storlets.sbus.client.exceptions import SBusClientIOError, \
     SBusClientMalformedResponse, SBusClientSendError
diff --git a/tests/unit/sbus/client/test_client.py b/tests/unit/sbus/client/test_client.py
index b55f9cf3..f6e4eb77 100644
--- a/tests/unit/sbus/client/test_client.py
+++ b/tests/unit/sbus/client/test_client.py
@@ -13,12 +13,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from contextlib import contextmanager
+import errno
 import json
-import mock
 import os
 import unittest
-import errno
-from contextlib import contextmanager
+from unittest import mock
 
 from storlets.sbus.client.exceptions import SBusClientSendError, \
     SBusClientMalformedResponse
diff --git a/tests/unit/swift_middleware/handlers/__init__.py b/tests/unit/swift_middleware/handlers/__init__.py
index 4e785855..c0d8faf6 100644
--- a/tests/unit/swift_middleware/handlers/__init__.py
+++ b/tests/unit/swift_middleware/handlers/__init__.py
@@ -13,8 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import mock
 import unittest
+from unittest import mock
 
 from storlets.gateway.gateways.stub import StorletGatewayStub
 from storlets.swift_middleware import storlet_handler
diff --git a/tests/unit/swift_middleware/handlers/test_base.py b/tests/unit/swift_middleware/handlers/test_base.py
index 916bc3cc..3ef24897 100644
--- a/tests/unit/swift_middleware/handlers/test_base.py
+++ b/tests/unit/swift_middleware/handlers/test_base.py
@@ -13,10 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import mock
-import unittest
 from contextlib import contextmanager
 from io import StringIO
+import unittest
+from unittest import mock
 
 from swift.common.swob import Request
 from storlets.gateway.common.exceptions import FileManagementError
diff --git a/tests/unit/swift_middleware/handlers/test_obj.py b/tests/unit/swift_middleware/handlers/test_obj.py
index c118d590..4d23851c 100644
--- a/tests/unit/swift_middleware/handlers/test_obj.py
+++ b/tests/unit/swift_middleware/handlers/test_obj.py
@@ -13,8 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import mock
 import unittest
+from unittest import mock
 
 from swift.common.swob import Request, HTTPOk, HTTPCreated
 from storlets.swift_middleware.handlers import StorletObjectHandler
diff --git a/tests/unit/swift_middleware/handlers/test_proxy.py b/tests/unit/swift_middleware/handlers/test_proxy.py
index a4075ed7..60e6a8cb 100644
--- a/tests/unit/swift_middleware/handlers/test_proxy.py
+++ b/tests/unit/swift_middleware/handlers/test_proxy.py
@@ -13,9 +13,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import mock
-import unittest
 import itertools
+import unittest
+from unittest import mock
 
 from contextlib import contextmanager
 from swift.common.swob import Request, HTTPOk, HTTPCreated, HTTPAccepted, \
diff --git a/tests/unit/tools/extensions/test_ipython.py b/tests/unit/tools/extensions/test_ipython.py
index 5dd6fa9f..26c82a2e 100644
--- a/tests/unit/tools/extensions/test_ipython.py
+++ b/tests/unit/tools/extensions/test_ipython.py
@@ -14,13 +14,14 @@
 # limitations under the License.
 
 from IPython.core.error import UsageError
+import itertools
 from io import FileIO as file
 from io import StringIO
-from storlets.tools.extensions.ipython import StorletMagics
-import unittest
-import mock
 import os
-import itertools
+import unittest
+from unittest import mock
+
+from storlets.tools.extensions.ipython import StorletMagics
 
 
 class FakeConnection(object):
diff --git a/tests/unit/tools/test_deploy_storlet.py b/tests/unit/tools/test_deploy_storlet.py
index 245ee333..e971a342 100644
--- a/tests/unit/tools/test_deploy_storlet.py
+++ b/tests/unit/tools/test_deploy_storlet.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 
 import unittest
-import mock
+from unittest import mock
 from storlets.tools.deploy_storlet import main