diff --git a/stubs/Authlib/authlib/integrations/requests_client/oauth2_session.pyi b/stubs/Authlib/authlib/integrations/requests_client/oauth2_session.pyi
index f358acc47ca5..0b642d545275 100644
--- a/stubs/Authlib/authlib/integrations/requests_client/oauth2_session.pyi
+++ b/stubs/Authlib/authlib/integrations/requests_client/oauth2_session.pyi
@@ -1,43 +1,46 @@
-from _typeshed import Incomplete
+from collections.abc import Callable
+from typing import Any, ClassVar, TypeVar
 
 from authlib.oauth2.auth import ClientAuth, TokenAuth
 from authlib.oauth2.client import OAuth2Client
+from oauthlib.oauth2 import OAuth2Token
+from requests import Request, Response, Session
+from requests.auth import AuthBase
 
 from ..base_client import OAuthError
 
 __all__ = ["OAuth2Session", "OAuth2Auth"]
 
-# Inherits from requests.auth.AuthBase
-class OAuth2Auth(TokenAuth):
+_R = TypeVar("_R", bound=Request)
+
+class OAuth2Auth(AuthBase, TokenAuth):
     def ensure_active_token(self) -> None: ...
-    def __call__(self, req): ...
+    def __call__(self, req: _R) -> _R: ...
 
-# Inherits from requests.auth.AuthBase
-class OAuth2ClientAuth(ClientAuth):
-    def __call__(self, req): ...
+class OAuth2ClientAuth(AuthBase, ClientAuth):
+    def __call__(self, req: _R) -> _R: ...
 
-# Inherits from requests.Session
-class OAuth2Session(OAuth2Client):
-    client_auth_class = OAuth2ClientAuth
-    token_auth_class = OAuth2Auth
-    oauth_error_class = OAuthError  # type: ignore[assignment]
-    SESSION_REQUEST_PARAMS: tuple[str, ...]  # type: ignore[assignment]
-    default_timeout: Incomplete
+class OAuth2Session(OAuth2Client, Session):
+    client_auth_class: ClassVar[type[OAuth2ClientAuth]]
+    token_auth_class: ClassVar[type[OAuth2Auth]]
+    oauth_error_class: ClassVar[type[OAuthError]]
+    SESSION_REQUEST_PARAMS: ClassVar[tuple[str, ...]]
+    default_timeout: float | tuple[float | None, float | None] | None
     def __init__(
         self,
-        client_id=None,
-        client_secret=None,
-        token_endpoint_auth_method=None,
-        revocation_endpoint_auth_method=None,
-        scope=None,
-        state=None,
-        redirect_uri=None,
-        token=None,
-        token_placement="header",
-        update_token=None,
-        leeway=60,
-        default_timeout=None,
+        client_id: str | None = None,
+        client_secret: str | None = None,
+        token_endpoint_auth_method: str | None = None,
+        revocation_endpoint_auth_method: str | None = None,
+        scope: str | None = None,
+        state: str | None = None,
+        redirect_uri: str | None = None,
+        token: dict[str, Any] | None = None,
+        token_placement: str = ...,
+        update_token: Callable[[OAuth2Token], None] | None = None,
+        leeway: int = ...,
+        default_timeout: float | tuple[float | None, float | None] | None = None,
         **kwargs,
     ) -> None: ...
-    def fetch_access_token(self, url=None, **kwargs): ...
-    def request(self, method, url, withhold_token=False, auth=None, **kwargs): ...
+    def fetch_access_token(self, url: str | None = None, **kwargs) -> OAuth2Token: ...
+    def request(self, method: str, url: str, withhold_token: bool = False, auth=None, **kwargs) -> Response: ...