diff --git a/include/wx/filename.h b/include/wx/filename.h
index 6f3273257d..7eff2e8783 100644
--- a/include/wx/filename.h
+++ b/include/wx/filename.h
@@ -27,6 +27,7 @@
 #include "wx/filefn.h"
 #include "wx/datetime.h"
 #include "wx/intl.h"
+#include "wx/longlong.h"
 
 #if wxUSE_FILE
 class WXDLLIMPEXP_FWD_BASE wxFile;