diff --git a/include/wx/dir.h b/include/wx/dir.h
index 980e5f2138..4ac1dffbf5 100644
--- a/include/wx/dir.h
+++ b/include/wx/dir.h
@@ -14,6 +14,7 @@
 
 #include "wx/longlong.h"
 #include "wx/string.h"
+#include "wx/filefn.h"      // for wxS_DIR_DEFAULT
 
 class WXDLLIMPEXP_FWD_BASE wxArrayString;