diff --git a/backend/app/api/gallery.py b/backend/app/api/gallery.py
index 5021c59..678637f 100644
--- a/backend/app/api/gallery.py
+++ b/backend/app/api/gallery.py
@@ -137,7 +137,11 @@ async def similar():
     except (KeyError, ValueError):
         return jsonify({"error": "similar_to query param required"}), 400
     # post_id is the exclusive post-detail view — not a similarity scope.
-    scope = {k: v for k, v in filters.items() if k != "post_id"}
+    # include_hidden is a gallery-browse flag; similar() has its OWN presentation
+    # exclusion (a similarity-quality concern, #1274), so drop it here (#141).
+    scope = {
+        k: v for k, v in filters.items() if k not in ("post_id", "include_hidden")
+    }
     async with get_session() as session:
         svc = GalleryService(session)
         try: