diff --git a/requirements_testing.txt b/requirements_testing.txt
index 848673c..94cdd59 100644
--- a/requirements_testing.txt
+++ b/requirements_testing.txt
@@ -6,6 +6,6 @@ pytest-cov==5.0.0
 pytest-icdiff==0.9
 ruff==0.6.8
 setuptools==75.1.0
-tox==4.20.0
+tox==4.21.2
 tox-gh-actions==3.2.0
 mypy==1.11.2