diff --git a/requirements_dev.txt b/requirements_dev.txt
index 1aeaea77..7662ae23 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -4,7 +4,7 @@ wheel==0.31.1
 watchdog==0.8.3
 flake8==3.5.0
 mock==2.0.0
-tox==3.0.0
+tox==3.1.1
 coverage==4.5.1
 Sphinx==1.7.5
 cryptography==2.2.2