diff --git a/stubs/requests/requests/models.pyi b/stubs/requests/requests/models.pyi
index 143ca7548da3..38fb47453776 100644
--- a/stubs/requests/requests/models.pyi
+++ b/stubs/requests/requests/models.pyi
@@ -74,7 +74,7 @@ class Request(RequestHooksMixin):
 class PreparedRequest(RequestEncodingMixin, RequestHooksMixin):
     method: str | None
     url: str | None
-    headers: CaseInsensitiveDict[str | bytes]
+    headers: CaseInsensitiveDict[str]
     body: bytes | str | None
     hooks: Any
     def __init__(self) -> None: ...