diff --git a/gdk/wayland/gdkselection-wayland.c b/gdk/wayland/gdkselection-wayland.c
index b31af85139..b98caa8ddf 100644
--- a/gdk/wayland/gdkselection-wayland.c
+++ b/gdk/wayland/gdkselection-wayland.c
@@ -479,7 +479,7 @@ static const struct gtk_primary_selection_offer_listener primary_offer_listener
   primary_offer_offer,
 };
 
-SelectionData *
+static SelectionData *
 selection_lookup_offer_by_atom (GdkWaylandSelection *selection,
                                 GdkAtom              selection_atom)
 {