diff --git a/Include/cStringIO.h b/Include/cStringIO.h
index 224f8ffcd82..50921d9e84d 100644
--- a/Include/cStringIO.h
+++ b/Include/cStringIO.h
@@ -1,5 +1,5 @@
-#ifndef CSTRINGIO_INCLUDED
-#define CSTRINGIO_INCLUDED
+#ifndef Py_CSTRINGIO_H
+#define Py_CSTRINGIO_H
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -60,4 +60,4 @@ static struct PycStringIO_CAPI {
 #ifdef __cplusplus
 }
 #endif
-#endif /* CSTRINGIO_INCLUDED */
+#endif /* !Py_CSTRINGIO_H */
diff --git a/Include/complexobject.h b/Include/complexobject.h
index f5b755d60a2..e59bf2ca957 100644
--- a/Include/complexobject.h
+++ b/Include/complexobject.h
@@ -1,7 +1,7 @@
 /* Complex number structure */
 
-#ifndef COMPLEXOBJECT_H
-#define COMPLEXOBJECT_H
+#ifndef Py_COMPLEXOBJECT_H
+#define Py_COMPLEXOBJECT_H
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -55,4 +55,4 @@ PyAPI_FUNC(Py_complex) PyComplex_AsCComplex(PyObject *op);
 #ifdef __cplusplus
 }
 #endif
-#endif /* !COMPLEXOBJECT_H */
+#endif /* !Py_COMPLEXOBJECT_H */