diff --git a/Modules/_copy.c b/Modules/_copy.c
index 68d2016f8c7421..52abb725e2b8c0 100644
--- a/Modules/_copy.c
+++ b/Modules/_copy.c
@@ -4,6 +4,7 @@
 
 #include "Python.h"
 #include "pycore_moduleobject.h"  // _PyModule_GetState()
+#include "pycore_object.h"  // _PyNone_Type, _PyNotImplemented_Type
 #include "clinic/_copy.c.h"
 
 /*[clinic input]