diff --git a/pyproject.toml b/pyproject.toml
index 66946a85..4c4990a9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -46,7 +46,7 @@ dev = [
   "pre-commit==4.3.0 ; python_version>='3.9'",
   "tox==3.27.1 ; python_version<'3.8'",
   "tox==4.24.1 ; python_version>='3.8' and python_version<'3.9'",
-  "tox==4.30.2 ; python_version>='3.9'",
+  "tox==4.56.1 ; python_version>='3.9'",
   # Testing framework.
   "pytest==6.1.2 ; python_version<'3.8'",
   "pytest==8.3.2 ; python_version>='3.8' and python_version<'3.9'",