diff --git a/tox.ini b/tox.ini
index 54b0723..579aece 100644
--- a/tox.ini
+++ b/tox.ini
@@ -18,7 +18,7 @@ deps =
   pytest-django
   pytest!=5.3.3
   WebTest
-  mock
+  mock<4
   httmock
   python-dateutil
   pylint