diff --git a/requirements_dev.txt b/requirements_dev.txt
index 9d7da80..e837727 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -2,7 +2,7 @@ bumpversion==0.5.3
 wheel==0.30.0
 watchdog==0.8.3
 flake8==3.5.0
-tox==2.9.1
+tox==3.14.6
 coverage==4.4.2
 Sphinx==1.6.4
 cryptography==2.1.4