diff --git a/fastapi/_compat/v2.py b/fastapi/_compat/v2.py
index a17d62556..7a9ee229f 100644
--- a/fastapi/_compat/v2.py
+++ b/fastapi/_compat/v2.py
@@ -384,7 +384,10 @@ def _remap_definitions_and_field_mappings(
     Dict[str, Any],
 ]:
     old_name_to_new_name_map = {}
-    for field_key, schema in field_mapping.items():
+    for field_key, schema in sorted(
+        field_mapping.items(),
+        key=lambda x: model_name_map.get(x[0][0].type_, ""),
+    ):
         model = field_key[0].type_
         if model not in model_name_map or "$ref" not in schema:
             continue