Three Bridges, known formally as Windmill Bridge, is a three-level crossing of transportation routes in Southall, west London, England.

Designed by Isambard Kingdom Brunel, the project was Brunel's last to be finished before he died on 15 September 1859.

The structure is a scheduled monument and is adjacent to an eponymous park.

[2] Brunel arranged the two cast iron bridges to allow the routes of the Grand Junction Canal, Great Western and Brentford Railway, and Windmill Lane to cross each other, with the road above the canal which is above the railway.

[3] As the railway was the most recent addition, the design allowed the railway to be in a deep cutting so it wasn't visible from and didn't enter Osterley Park as well as being more economical.