diff --git a/evals/cli/oaieval.py b/evals/cli/oaieval.py
index 06c3c5f6e5..a8927dda4c 100644
--- a/evals/cli/oaieval.py
+++ b/evals/cli/oaieval.py
@@ -155,7 +155,11 @@ def to_number(x: str) -> Union[int, float, str]:
         return {k: to_number(v) for k, v in str_dict.items()}
 
     extra_eval_params = parse_extra_eval_params(args.extra_eval_params)
-    eval_spec.args.update(extra_eval_params)
+
+    if eval_spec.args is None:
+        eval_spec.args = extra_eval_params
+    else:
+        eval_spec.args.update(extra_eval_params)
 
     # If the user provided an argument to --completion_args, parse it into a dict here, to be passed to the completion_fn creation **kwargs
     completion_args = args.completion_args.split(",")