diff --git a/tox.ini b/tox.ini
index a7bf6d242..cd04d0c57 100644
--- a/tox.ini
+++ b/tox.ini
@@ -81,7 +81,7 @@ setenv =
     PYTHONWARNDEFAULTENCODING=
 
 [testenv:docs]
-basepython = python3.9 # sync with rtd to get errors
+basepython = python3.12 # sync with rtd to get errors
 usedevelop = True
 deps =
     -r{toxinidir}/doc/en/requirements.txt