diff --git a/python_modules/dagster-graphql/dagster_graphql/implementation/execution/backfill.py b/python_modules/dagster-graphql/dagster_graphql/implementation/execution/backfill.py
index 5c382384a5536..0099a5f92b94b 100644
--- a/python_modules/dagster-graphql/dagster_graphql/implementation/execution/backfill.py
+++ b/python_modules/dagster-graphql/dagster_graphql/implementation/execution/backfill.py
@@ -469,4 +469,4 @@ def delete_partition_backfill(
 
     graphene_info.context.instance.delete_backfill(backfill_id)
 
-    return GrapheneDeleteBackfillSuccess(backfill_id=backfill_id)
+    return GrapheneDeleteBackfillSuccess(backfillId=backfill_id)