diff --git a/src/hb-common.cc b/src/hb-common.cc
index c9a40295a..282a8e4d0 100644
--- a/src/hb-common.cc
+++ b/src/hb-common.cc
@@ -632,6 +632,7 @@ hb_script_get_horizontal_direction (hb_script_t script)
     case HB_SCRIPT_OLD_HUNGARIAN:
     case HB_SCRIPT_OLD_ITALIC:
     case HB_SCRIPT_RUNIC:
+    case HB_SCRIPT_TIFINAGH:
 
       return HB_DIRECTION_INVALID;
   }