diff --git a/python/sglang/bench_serving.py b/python/sglang/bench_serving.py
index 10ce965be..41e1a6109 100644
--- a/python/sglang/bench_serving.py
+++ b/python/sglang/bench_serving.py
@@ -71,6 +71,14 @@ def remove_prefix(text: str, prefix: str) -> str:
     return text[len(prefix) :] if text.startswith(prefix) else text
 
 
+def get_auth_headers() -> Dict[str, str]:
+    api_key = os.environ.get("OPENAI_API_KEY")
+    if api_key:
+        return {"Authorization": f"Bearer {api_key}"}
+    else:
+        return {}
+
+
 # trt llm not support ignore_eos
 # https://github.com/triton-inference-server/tensorrtllm_backend/issues/505
 async def async_request_trt_llm(
@@ -165,7 +173,7 @@ async def async_request_openai_completions(
             "ignore_eos": not args.disable_ignore_eos,
             **request_func_input.extra_request_body,
         }
-        headers = {"Authorization": f"Bearer {os.environ.get('OPENAI_API_KEY')}"}
+        headers = get_auth_headers()
 
         output = RequestFuncOutput()
         output.prompt_len = request_func_input.prompt_len
@@ -244,7 +252,7 @@ async def async_request_truss(
             "ignore_eos": not args.disable_ignore_eos,
             **request_func_input.extra_request_body,
         }
-        headers = {"Authorization": f"Bearer {os.environ.get('OPENAI_API_KEY')}"}
+        headers = get_auth_headers()
 
         output = RequestFuncOutput()
         output.prompt_len = request_func_input.prompt_len
@@ -325,7 +333,7 @@ async def async_request_sglang_generate(
             "logprob_start_len": -1,
             **request_func_input.extra_request_body,
         }
-        headers = {}
+        headers = get_auth_headers()
 
         output = RequestFuncOutput()
         output.prompt_len = request_func_input.prompt_len
@@ -1238,7 +1246,7 @@ def run_benchmark(args_: argparse.Namespace):
             )
             sys.exit(1)
         try:
-            response = requests.get(model_url)
+            response = requests.get(model_url, headers=get_auth_headers())
             model_list = response.json().get("data", [])
             args.model = model_list[0]["id"] if model_list else None
         except Exception as e: