diff --git a/lower-constraints.txt b/lower-constraints.txt
index 368820fd48..d083c95c58 100644
--- a/lower-constraints.txt
+++ b/lower-constraints.txt
@@ -64,7 +64,6 @@ logutils==0.3.5
 Mako==1.0.7
 MarkupSafe==1.0
 mccabe==0.4.0
-mock==2.0.0
 monotonic==1.4
 mox3==0.25.0
 msgpack==0.5.6
diff --git a/octavia/hacking/checks.py b/octavia/hacking/checks.py
index 52070bb719..eec747609b 100644
--- a/octavia/hacking/checks.py
+++ b/octavia/hacking/checks.py
@@ -66,6 +66,8 @@ untranslated_exception_re = re.compile(r"raise (?:\w*)\((.*)\)")
 no_eventlet_re = re.compile(r'(import|from)\s+[(]?eventlet')
 no_line_continuation_backslash_re = re.compile(r'.*(\\)\n')
 no_logging_re = re.compile(r'(import|from)\s+[(]?logging')
+import_mock_re = re.compile(r"\bimport[\s]+mock\b")
+import_from_mock_re = re.compile(r"\bfrom[\s]+mock[\s]+import\b")
 
 
 def _translation_checks_not_enforced(filename):
@@ -258,3 +260,18 @@ def check_no_logging_imports(logical_line):
     if no_logging_re.match(logical_line):
         msg = 'O348 Usage of Python logging module not allowed, use oslo_log'
         yield logical_line.index('logging'), msg
+
+
+@core.flake8ext
+def check_no_import_mock(logical_line):
+    """O349 - Test code must not import mock library.
+
+    :param logical_line: The logical line to check.
+    :returns: None if the logical line passes the check, otherwise a tuple
+              is yielded that contains the offending index in logical line
+              and a message describe the check validation failure.
+    """
+    if (import_mock_re.match(logical_line) or
+            import_from_mock_re.match(logical_line)):
+        msg = 'O349 Test code must not import mock library, use unittest.mock'
+        yield 0, msg
diff --git a/octavia/tests/unit/api/drivers/driver_agent/test_driver_updater.py b/octavia/tests/unit/api/drivers/driver_agent/test_driver_updater.py
index 46c9a27298..dd453516d5 100644
--- a/octavia/tests/unit/api/drivers/driver_agent/test_driver_updater.py
+++ b/octavia/tests/unit/api/drivers/driver_agent/test_driver_updater.py
@@ -13,13 +13,13 @@
 #    under the License.
 import copy
 from unittest import mock
+from unittest.mock import call
 
-from mock import call
+from octavia_lib.api.drivers import exceptions as driver_exceptions
+from octavia_lib.common import constants as lib_consts
 
 from octavia.api.drivers.driver_agent import driver_updater
 import octavia.tests.unit.base as base
-from octavia_lib.api.drivers import exceptions as driver_exceptions
-from octavia_lib.common import constants as lib_consts
 
 
 class TestDriverUpdater(base.TestCase):
diff --git a/tox.ini b/tox.ini
index e2f81631ad..9eb64feb5c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -190,6 +190,7 @@ extension =
   O346 = checks:check_line_continuation_no_backslash
   O347 = checks:revert_must_have_kwargs
   O348 = checks:check_no_logging_imports
+  O349 = checks:check_no_import_mock
 paths =
   ./octavia/hacking