diff --git a/mypy_self_check.ini b/mypy_self_check.ini
index 7198a1f6f342..8b38cf7534a0 100644
--- a/mypy_self_check.ini
+++ b/mypy_self_check.ini
@@ -1,6 +1,7 @@
 [mypy]
 
 strict = True
+strict_bytes = True
 local_partial_types = True
 disallow_any_unimported = True
 show_traceback = True