diff --git a/requirements.txt b/requirements.txt
index cfd0c8476..ea10eaa53 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -9,7 +9,7 @@ flake8==3.7.6
 
 # Testing
 # ------------------------------------------------------------------------------
-tox==3.8.6
+tox==3.9.0
 pytest==4.4.1
 pytest_cases==1.6.2
 pytest-cookies==0.3.0