diff --git a/stubs/requests-oauthlib/requests_oauthlib/oauth1_auth.pyi b/stubs/requests-oauthlib/requests_oauthlib/oauth1_auth.pyi
index 2db50b97e4b3..d5fcd8ace105 100644
--- a/stubs/requests-oauthlib/requests_oauthlib/oauth1_auth.pyi
+++ b/stubs/requests-oauthlib/requests_oauthlib/oauth1_auth.pyi
@@ -23,7 +23,7 @@ class OAuth1(AuthBase):
         signature_type="AUTH_HEADER",
         rsa_key: Incomplete | None = None,
         verifier: Incomplete | None = None,
-        decoding: str = "utf-8",
+        decoding: str | None = "utf-8",
         client_class: type[Client] | None = None,
         force_include_body: bool = False,
         *,