diff --git a/tox.ini b/tox.ini
index 286cd82..5a536e7 100644
--- a/tox.ini
+++ b/tox.ini
@@ -12,7 +12,7 @@ changedir=
 deps =
     mock
     psycopg2
-    pytest
+    pytest==3.6.4
     pytest-django
     pytest-flake8
     pytest-cov