diff --git a/gtk/gtkgesture.c b/gtk/gtkgesture.c
index f9673ebf14..b45ab6e17e 100644
--- a/gtk/gtkgesture.c
+++ b/gtk/gtkgesture.c
@@ -1159,7 +1159,7 @@ gtk_gesture_get_last_updated_sequence (GtkGesture *gesture)
 /**
  * gtk_gesture_get_last_event:
  * @gesture: a #GtkGesture
- * @sequence: a #GdkEventSequence
+ * @sequence: (nullable): a #GdkEventSequence
  *
  * Returns the last event that was processed for @sequence.
  *