diff --git a/src/msw/textctrl.cpp b/src/msw/textctrl.cpp
index 1fb31b72c7..22aacd1548 100644
--- a/src/msw/textctrl.cpp
+++ b/src/msw/textctrl.cpp
@@ -50,6 +50,7 @@
 #include <windowsx.h>
 
 #include "wx/msw/private.h"
+#include "wx/msw/winundef.h"
 #include "wx/msw/mslu.h"
 
 #include <string.h>