diff --git a/include/wtypes.idl b/include/wtypes.idl
index 754258839d7..5a09ed717cb 100644
--- a/include/wtypes.idl
+++ b/include/wtypes.idl
@@ -33,7 +33,7 @@ interface IWinTypes
 /******************** BASIC WIN32 TYPES ********************/
 cpp_quote("#if 0 /* winnt.h */") /* don't redefine these */
 
-typedef unsigned char BYTE;
+typedef byte BYTE;
 typedef unsigned short WORD;
 typedef unsigned long DWORD;
 typedef long BOOL;