diff --git a/tox.ini b/tox.ini
index 9add57684..5efa3638b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -163,6 +163,7 @@ deps =
     pyflakes==1.0.0
     flake8-string-format==0.2.1
     flake8-deprecated==0.2
+    flake8-mock==0.2
 commands =
     {envpython} -m flake8