diff --git a/gtk/gtkshow.c b/gtk/gtkshow.c
index 6fb7e0f5ad..1bec9808ef 100644
--- a/gtk/gtkshow.c
+++ b/gtk/gtkshow.c
@@ -82,7 +82,7 @@ gtk_show_uri (GdkScreen    *screen,
 
 /**
  * gtk_show_uri_on_window:
- * @parent: parent window
+ * @parent: (allow-none): parent window
  * @uri: the uri to show
  * @timestamp: a timestamp to prevent focus stealing
  * @error: a #GError that is returned in case of errors