diff --git a/gtk/gtktextmark.c b/gtk/gtktextmark.c
index dc8f78c44f..ba2544ab4f 100644
--- a/gtk/gtktextmark.c
+++ b/gtk/gtktextmark.c
@@ -294,7 +294,7 @@ gtk_text_mark_get_visible (GtkTextMark *mark)
  * 
  * Returns the mark name; returns NULL for anonymous marks.
  * 
- * Returns: mark name
+ * Returns: (nullable): mark name
  **/
 const char *
 gtk_text_mark_get_name (GtkTextMark *mark)