diff --git a/setup.cfg b/setup.cfg
index 2f375b29a..51a4a853c 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -30,6 +30,7 @@ console_scripts =
     openstack-inventory = openstack.cloud.cmd.inventory:main
 
 [mypy]
+python_version = 3.9
 show_column_numbers = true
 show_error_context = true
 ignore_missing_imports = true