diff --git a/requirements_dev.txt b/requirements_dev.txt
index 1a33e65..7d0185b 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -3,7 +3,7 @@ bumpversion==0.5.3
 wheel==0.29.0
 watchdog==0.8.3
 flake8==3.2.1
-tox==2.4.1
+tox==2.5.0
 coverage==4.3.1
 Sphinx==1.5
 cryptography==1.7.1