diff --git a/Include/internal/pycore_modsupport.h b/Include/internal/pycore_modsupport.h
index c661f1d82a84f6..614e9f93751834 100644
--- a/Include/internal/pycore_modsupport.h
+++ b/Include/internal/pycore_modsupport.h
@@ -1,8 +1,6 @@
 #ifndef Py_INTERNAL_MODSUPPORT_H
 #define Py_INTERNAL_MODSUPPORT_H
 
-#include "pycore_lock.h"    // _PyOnceFlag
-
 #ifdef __cplusplus
 extern "C" {
 #endif