diff --git a/packages/mbed-greentea/test/mbed_gt_cmake_handlers.py b/packages/mbed-greentea/test/mbed_gt_cmake_handlers.py
index 7681c1905e..d703d85f94 100644
--- a/packages/mbed-greentea/test/mbed_gt_cmake_handlers.py
+++ b/packages/mbed-greentea/test/mbed_gt_cmake_handlers.py
@@ -16,7 +16,10 @@
 """
 
 import os
-import mock
+try:
+   from unittest import mock
+except ImportError
+   import mock
 import six
 import sys
 import unittest
diff --git a/packages/mbed-host-tests/test/conn_primitive_remote.py b/packages/mbed-host-tests/test/conn_primitive_remote.py
index b5365f4e93..87c09aac3c 100644
--- a/packages/mbed-host-tests/test/conn_primitive_remote.py
+++ b/packages/mbed-host-tests/test/conn_primitive_remote.py
@@ -16,7 +16,10 @@
 """
 
 import unittest
-import mock
+try:
+   from unittest import mock
+except ImportError
+   import mock
 
 from mbed_host_tests.host_tests_conn_proxy.conn_primitive_remote import RemoteConnectorPrimitive
 
diff --git a/packages/mbed-host-tests/test/mps2_reset.py b/packages/mbed-host-tests/test/mps2_reset.py
index 07a030dcde..8dce79e313 100644
--- a/packages/mbed-host-tests/test/mps2_reset.py
+++ b/packages/mbed-host-tests/test/mps2_reset.py
@@ -16,7 +16,10 @@
 """
 
 import unittest
-import mock
+try:
+   from unittest import mock
+except ImportError
+   import mock
 import os
 import time
 
diff --git a/test/test/conn_primitive_remote.py b/test/test/conn_primitive_remote.py
index aaca449638..6cbb6859d6 100644
--- a/test/test/conn_primitive_remote.py
+++ b/test/test/conn_primitive_remote.py
@@ -14,7 +14,10 @@
 # limitations under the License.
 
 import unittest
-import mock
+try:
+   from unittest import mock
+except ImportError
+   import mock
 
 from mbed_os_tools.test.host_tests_conn_proxy.conn_primitive_remote import RemoteConnectorPrimitive
 
diff --git a/test/test/mbed_gt_cmake_handlers.py b/test/test/mbed_gt_cmake_handlers.py
index 775eeae616..eac17a8693 100644
--- a/test/test/mbed_gt_cmake_handlers.py
+++ b/test/test/mbed_gt_cmake_handlers.py
@@ -14,7 +14,10 @@
 # limitations under the License.
 
 import os
-import mock
+try:
+   from unittest import mock
+except ImportError
+   import mock
 import six
 import sys
 import unittest
diff --git a/test/test/mbed_gt_greentea_dlm.py b/test/test/mbed_gt_greentea_dlm.py
index 4163d78144..f921aeb02a 100644
--- a/test/test/mbed_gt_greentea_dlm.py
+++ b/test/test/mbed_gt_greentea_dlm.py
@@ -20,7 +20,10 @@
 import unittest
 
 from lockfile import LockFile
-from mock import patch
+try:
+    from unittest.mock import patch
+except ImportError:
+    from mock import patch
 from mbed_os_tools.test import mbed_greentea_dlm
 
 home_dir = tempfile.mkdtemp()
diff --git a/test/test/mbed_gt_hooks.py b/test/test/mbed_gt_hooks.py
index 2089a35fbd..4646969f91 100644
--- a/test/test/mbed_gt_hooks.py
+++ b/test/test/mbed_gt_hooks.py
@@ -17,7 +17,10 @@
 import sys
 import unittest
 
-from mock import patch
+try:
+    from unittest.mock import patch
+except ImportError:
+    from mock import patch
 from mbed_os_tools.test.mbed_greentea_hooks import GreenteaCliTestHook
 from mbed_os_tools.test.mbed_greentea_hooks import LcovHook
 
diff --git a/test/test/mbed_gt_report_api.py b/test/test/mbed_gt_report_api.py
index 2ad765f92c..8080b6c29f 100644
--- a/test/test/mbed_gt_report_api.py
+++ b/test/test/mbed_gt_report_api.py
@@ -20,7 +20,10 @@
 import tempfile
 import unittest
 
-from mock import patch
+try:
+    from unittest.mock import patch
+except ImportError:
+    from mock import patch
 from mbed_os_tools.test import mbed_report_api
 
 class GreenteaReportApiFunctionality(unittest.TestCase):
diff --git a/test/test/mbed_gt_target_info.py b/test/test/mbed_gt_target_info.py
index 64a2c83032..ef4789db61 100644
--- a/test/test/mbed_gt_target_info.py
+++ b/test/test/mbed_gt_target_info.py
@@ -20,7 +20,10 @@
 
 from six import StringIO
 
-from mock import patch
+try:
+    from unittest.mock import patch
+except ImportError:
+    from mock import patch
 from mbed_os_tools.test import mbed_target_info
 
 
diff --git a/test/test/mbed_gt_test_api.py b/test/test/mbed_gt_test_api.py
index 2bb3b3ffbf..7aca27db3c 100644
--- a/test/test/mbed_gt_test_api.py
+++ b/test/test/mbed_gt_test_api.py
@@ -15,8 +15,10 @@
 
 import unittest
 from mbed_os_tools.test import mbed_test_api
-from mock import patch, MagicMock
-
+try:
+    from unittest.mock import patch, MagicMock
+except ImportError:
+    from mock import patch, MagicMock
 
 class GreenteaTestAPI(unittest.TestCase):
 
diff --git a/test/test/mocks/environment/linux.py b/test/test/mocks/environment/linux.py
index d348ff343f..a00cbcf5d3 100644
--- a/test/test/mocks/environment/linux.py
+++ b/test/test/mocks/environment/linux.py
@@ -1,6 +1,9 @@
 import os
 from builtins import super
-from mock import MagicMock
+try:
+    from unittest.mock import MagicMock
+except ImportError:
+    from mock import MagicMock
 
 from .posix import MockTestEnvironmentPosix
 
diff --git a/test/test/mps2_reset.py b/test/test/mps2_reset.py
index 9cf09f9a06..b56d73ee1a 100644
--- a/test/test/mps2_reset.py
+++ b/test/test/mps2_reset.py
@@ -14,7 +14,10 @@
 # limitations under the License.
 
 import unittest
-import mock
+try:
+   from unittest import mock
+except ImportError
+   import mock
 import os
 import time
 
diff --git a/test/test/test_conn_primitive_serial.py b/test/test/test_conn_primitive_serial.py
index 30d57ae2bc..f88b9f82b5 100644
--- a/test/test/test_conn_primitive_serial.py
+++ b/test/test/test_conn_primitive_serial.py
@@ -14,7 +14,10 @@
 # limitations under the License.
 
 import unittest
-import mock
+try:
+   from unittest import mock
+except ImportError
+   import mock
 
 from mbed_os_tools.test.host_tests_conn_proxy.conn_primitive_serial import SerialConnectorPrimitive
 from mbed_os_tools.test.host_tests_conn_proxy.conn_primitive import ConnectorPrimitiveException
diff --git a/test/test/test_mbed_base.py b/test/test/test_mbed_base.py
index 56daa4b26b..a614730b66 100644
--- a/test/test/test_mbed_base.py
+++ b/test/test/test_mbed_base.py
@@ -13,7 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import shutil
-import mock
+try:
+   from unittest import mock
+except ImportError
+   import mock
 import os
 import unittest
 from tempfile import mkdtemp