diff --git a/gtk/gtkflowbox.h b/gtk/gtkflowbox.h
index fa059c3765..ba07f55e7a 100644
--- a/gtk/gtkflowbox.h
+++ b/gtk/gtkflowbox.h
@@ -101,8 +101,8 @@ struct _GtkFlowBoxChildClass
 
 /**
  * GtkFlowBoxCreateWidgetFunc:
- * @item: the item from the model for which to create a widget for
- * @user_data: user data from gtk_flow_box_bind_model()
+ * @item: (type GObject): the item from the model for which to create a widget for
+ * @user_data: (closure): user data from gtk_flow_box_bind_model()
  *
  * Called for flow boxes that are bound to a #GListModel with
  * gtk_flow_box_bind_model() for each item that gets added to the model.