diff --git a/include/wx/msw/tooltip.h b/include/wx/msw/tooltip.h
index c5fbe836a0..367fe18a53 100644
--- a/include/wx/msw/tooltip.h
+++ b/include/wx/msw/tooltip.h
@@ -12,6 +12,8 @@
 #ifndef _WX_MSW_TOOLTIP_H_
 #define _WX_MSW_TOOLTIP_H_
 
+#include "wx/object.h"
+
 class WXDLLEXPORT wxToolTip : public wxObject
 {
 public: