diff --git a/common/lib/xmodule/xmodule/contentstore/mongo.py b/common/lib/xmodule/xmodule/contentstore/mongo.py
index bf3fa0645f..2bd1123ea2 100644
--- a/common/lib/xmodule/xmodule/contentstore/mongo.py
+++ b/common/lib/xmodule/xmodule/contentstore/mongo.py
@@ -428,7 +428,7 @@ class MongoContentStore(ContentStore):
 
     def ensure_indexes(self):
         # Index needed thru 'category' by `_get_all_content_for_course` and others. That query also takes a sort
-        # which can be `uploadDate`, `display_name`,
+        # which can be `uploadDate`, `displayname`,
         create_collection_index(
             self.fs_files,
             [