diff --git a/Objects/bytes_methods.c b/Objects/bytes_methods.c
index fe666c631c6..d0f784ecd46 100644
--- a/Objects/bytes_methods.c
+++ b/Objects/bytes_methods.c
@@ -1,3 +1,4 @@
+#define PY_SSIZE_T_CLEAN
 #include "Python.h"
 #include "bytes_methods.h"