diff --git a/requirements_dev.txt b/requirements_dev.txt
index ddd38e0..f6b756a 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -3,7 +3,7 @@ bumpversion==0.6.0
 wheel==0.32.3
 watchdog==0.9.0
 flake8==3.6.0
-tox==3.8.6
+tox==4.23.2
 Sphinx==2.1.2
 coverage==4.5.2
 twine==1.12.1