diff --git a/fairseq/models/fairseq_model.py b/fairseq/models/fairseq_model.py
index 7ca1c54308..e6a0512a58 100644
--- a/fairseq/models/fairseq_model.py
+++ b/fairseq/models/fairseq_model.py
@@ -35,7 +35,8 @@ def add_args(cls, parser):
         """Add model-specific arguments to the parser."""
         dc = getattr(cls, "__dataclass", None)
         if dc is not None:
-            gen_parser_from_dataclass(parser, dc())
+            # do not set defaults so that settings defaults from various architectures still works
+            gen_parser_from_dataclass(parser, dc(), delete_default=True)
 
     @classmethod
     def build_model(cls, args, task):