diff --git a/reactos/lib/sdk/ioevent/ioevent.c b/reactos/lib/sdk/ioevent/ioevent.c
index 2e4f882303c..6feb319e2d7 100644
--- a/reactos/lib/sdk/ioevent/ioevent.c
+++ b/reactos/lib/sdk/ioevent/ioevent.c
@@ -1,6 +1,7 @@
 #include <stdarg.h>
 
 #define COM_NO_WINDOWS_H
+#include "windef.h"
 #include "initguid.h"
 
 #include <ioevent.h>