diff --git a/src/hb-aat-layout.cc b/src/hb-aat-layout.cc
index 1912de0db..5a4e227ca 100644
--- a/src/hb-aat-layout.cc
+++ b/src/hb-aat-layout.cc
@@ -196,7 +196,7 @@ hb_aat_layout_compile_map (const hb_aat_map_builder_t *mapper,
 hb_bool_t
 hb_aat_layout_has_substitution (hb_face_t *face)
 {
-  return face->table.morx->has_data ();
+  return face->table.morx->has_data () ||
 	 face->table.mort->has_data ();
 }