The 19-year-old full-back has been a regular in Uwe Rosler's promotion-chasing side this season, making 27 appearances since arriving in west London in August.
Bidwell, who also spent a successful six months at Griffin Park last season, has agreed an extension until February 2.
Brentford say the deal is with a view to extending his stay further as the season progresses.
- Sports & Recreation
- Uwe Rosler