diff --git a/include/ole2.h b/include/ole2.h
index c9ecc1d..9536af5 100644
--- a/include/ole2.h
+++ b/include/ole2.h
@@ -8,6 +8,7 @@
 #include "wintypes.h"
 #include "winerror.h"
 #include "oleidl.h"
+#include "oleauto.h"
 
 /* OLE version */
 #define rmm             23