diff --git a/src/os2/toplevel.cpp b/src/os2/toplevel.cpp
index 9fbc3e6ae3..35738bac17 100644
--- a/src/os2/toplevel.cpp
+++ b/src/os2/toplevel.cpp
@@ -31,6 +31,7 @@
 #ifndef WX_PRECOMP
     #include "wx/app.h"
     #include "wx/toplevel.h"
+    #include "wx/dialog.h"
     #include "wx/string.h"
     #include "wx/log.h"
     #include "wx/intl.h"