diff --git a/requirements_dev.txt b/requirements_dev.txt
index 3719884..f53d4ab 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -5,7 +5,7 @@ wheel==0.33.4
 watchdog==0.9.0
 flake8==3.7.7
 pytest-mypy==0.3.2
-tox==3.12.1
+tox==4.23.0
 coverage==4.5.3
 Sphinx==2.1.0
 twine==1.13.0