diff --git a/stubs/requests/requests/utils.pyi b/stubs/requests/requests/utils.pyi
index 20dd0e0e8..f5805d81d 100644
--- a/stubs/requests/requests/utils.pyi
+++ b/stubs/requests/requests/utils.pyi
@@ -34,7 +34,7 @@ def unquote_header_value(value, is_filename: bool = False): ...
 def dict_from_cookiejar(cj): ...
 def add_dict_to_cookiejar(cj, cookie_dict): ...
 def get_encodings_from_content(content): ...
-def get_encoding_from_headers(headers): ...
+def get_encoding_from_headers(headers: Mapping[str, str]) -> str | None: ...
 def stream_decode_response_unicode(iterator, r): ...
 def iter_slices(string: str, slice_length: int | None) -> Generator[str, None, None]: ...
 def get_unicode_from_response(r): ...