diff --git a/vllm/attention/selector.py b/vllm/attention/selector.py
index 42f4284c..c2ec4376 100644
--- a/vllm/attention/selector.py
+++ b/vllm/attention/selector.py
@@ -1,4 +1,5 @@
 from functools import lru_cache
+from typing import Type
 
 import torch
 
@@ -10,7 +11,7 @@ logger = init_logger(__name__)
 
 
 @lru_cache(maxsize=None)
-def get_attn_backend(dtype: torch.dtype) -> AttentionBackend:
+def get_attn_backend(dtype: torch.dtype) -> Type[AttentionBackend]:
     if _can_use_flash_attn(dtype):
         logger.info("Using FlashAttention backend.")
         from vllm.attention.backends.flash_attn import (  # noqa: F401