diff --git a/gio/gtask.c b/gio/gtask.c
index 774cba793..e8c2ef282 100644
--- a/gio/gtask.c
+++ b/gio/gtask.c
@@ -1136,7 +1136,7 @@ g_task_get_context (GTask *task)
  *
  * Gets @task's #GCancellable
  *
- * Returns: (transfer none): @task's #GCancellable
+ * Returns: (nullable) (transfer none): @task's #GCancellable
  *
  * Since: 2.36
  */