diff --git a/firestore.indexes.json b/firestore.indexes.json
index bcee41d5..2b7ef839 100644
--- a/firestore.indexes.json
+++ b/firestore.indexes.json
@@ -100,6 +100,20 @@
         }
       ]
     },
+    {
+      "collectionGroup": "comments",
+      "queryScope": "COLLECTION",
+      "fields": [
+        {
+          "fieldPath": "userId",
+          "order": "ASCENDING"
+        },
+        {
+          "fieldPath": "createdTime",
+          "order": "ASCENDING"
+        }
+      ]
+    },
     {
       "collectionGroup": "comments",
       "queryScope": "COLLECTION_GROUP",