diff --git a/requirements/core.txt b/requirements/core.txt
index 46fc434..15ec4e1 100644
--- a/requirements/core.txt
+++ b/requirements/core.txt
@@ -1,4 +1,4 @@
-mock
+mock; python_version < '3.3'
 Django
 djangorestframework
 model-bakery~=1.1.0; python_version < '3'