diff --git a/extra/clutter/ffi/ffi.factor b/extra/clutter/ffi/ffi.factor
index b2d91928b0..300d1d85dc 100644
--- a/extra/clutter/ffi/ffi.factor
+++ b/extra/clutter/ffi/ffi.factor
@@ -5,6 +5,7 @@ gobject-introspection kernel system vocabs ;
 IN: clutter.ffi
 
 <<
+"gtk" require
 "atk.ffi" require
 "pango.cairo.ffi" require
 "clutter.cogl.ffi" require