diff --git a/tox.ini b/tox.ini
index dfcbf65b..5b11829f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -35,7 +35,7 @@ commands =
 [testenv:pep8]
 usedevelop = False
 deps =
-    flake8
+    flake8<3.6.0
 description =
     Run style checks
 commands =