diff --git a/setup.cfg b/setup.cfg
index 37d5a80e..26b4a9ba 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -72,6 +72,7 @@ per-file-ignores =
 
 [mypy]
 follow_imports = normal
+strict_optional = True
 
 [mypy-usb.*]
 ignore_missing_imports = True