diff --git a/requirements.txt b/requirements.txt
index eb992ed7..379ae48c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -8,6 +8,6 @@ flake8==3.5.0
 
 # Testing
 # ------------------------------------------------------------------------------
-tox==3.4.0
+tox==3.5.2
 pytest==3.8.2
 pytest-cookies==0.3.0