diff --git a/gtk/gtkboxlayout.c b/gtk/gtkboxlayout.c
index 0b88e39fcf..5d3ef2bd0d 100644
--- a/gtk/gtkboxlayout.c
+++ b/gtk/gtkboxlayout.c
@@ -91,6 +91,8 @@ gtk_box_layout_set_orientation (GtkBoxLayout   *self,
     _gtk_orientable_set_style_classes (GTK_ORIENTABLE (widget));
 
   gtk_layout_manager_layout_changed (layout_manager);
+
+  g_object_notify (G_OBJECT (self), "orientation");
 }
 
 static void