diff --git a/requirements.txt b/requirements.txt
index 7006d9c..32da40d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,7 +3,7 @@ bumpversion==0.5.3
 wheel==0.29.0
 watchdog==0.8.3
 flake8==2.6.0
-tox==2.3.1
+tox==3.8.4
 coverage==4.1
 Sphinx==1.4.8
 mock==2.0.0