diff --git a/requirements_dev.txt b/requirements_dev.txt
index e8e786d..8eddbdb 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -3,7 +3,7 @@ bumpversion==0.5.3
 wheel==0.33.1
 watchdog==0.9.0
 flake8==3.7.6
-tox==3.5.3
+tox==3.7.0
 coverage==4.5.1
 Sphinx==1.8.5
 cryptography==2.6.1