diff --git a/MdePkg/Include/Protocol/SmmStandbyButtonDispatch.h b/MdePkg/Include/Protocol/SmmStandbyButtonDispatch.h
index 79b0602a03..e8cd172e40 100644
--- a/MdePkg/Include/Protocol/SmmStandbyButtonDispatch.h
+++ b/MdePkg/Include/Protocol/SmmStandbyButtonDispatch.h
@@ -40,8 +40,8 @@ typedef struct _EFI_SMM_STANDBY_BUTTON_DISPATCH_PROTOCOL  EFI_SMM_STANDBY_BUTTON
 //    - OS Install Phase
 //
 typedef enum {
-  Entry,
-  Exit
+  StandbyButtonEntry,
+  StandbyButtonExit
 } EFI_STANDBY_BUTTON_PHASE;
 
 typedef struct {