diff --git a/requirements-dev.txt b/requirements-dev.txt
index f8054a5..e7d2f08 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -3,4 +3,4 @@ flake8==3.7.8
 flake8-bugbear==19.8.0;python_version>="3.5"
 flake8-tuple==0.4.0
 isort==4.3.21
-tox
+tox==3.14.0