diff --git a/requirements_dev.txt b/requirements_dev.txt
index 94dd2cc..c8f0a0a 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -5,7 +5,7 @@ wheel==0.33.6
 watchdog==0.9.0
 pytest==5.1.2
 coverage==4.5.4
-tox==3.13.2
+tox==4.23.0
 Sphinx==2.2.0
 twine==1.13.0
 pytest-runner==5.1