diff --git a/src/msw/textctrl.cpp b/src/msw/textctrl.cpp
index 05df7e86d2..e54f8ce99c 100644
--- a/src/msw/textctrl.cpp
+++ b/src/msw/textctrl.cpp
@@ -50,6 +50,7 @@
 #include "wx/textfile.h"
 
 #include <windowsx.h>
+#include "wx/msw/winundef.h"
 
 #include "wx/msw/private.h"