diff --git a/include/task.h b/include/task.h
index 5635dac..8750a32 100644
--- a/include/task.h
+++ b/include/task.h
@@ -8,6 +8,7 @@
 #define __WINE_TASK_H
 
 #include "windef.h"
+#include "wine/windef16.h"
 
 #include "pshpack1.h"