Westwood, Baillie and Co. was a Victorian ship builders, bridge builders and boilermakers based at London Yard, Cubitt Town, Poplar, East London. The company was established in 1856 by Robert Baillie and Joseph Westwood with James Campbell - It was known as Westwood, Baillie, Campbell and Co. In 1862 Campbell left the company and Westwood, Baillie and Co. was the result.

The company had difficulty with the decline in Thames shipbuilding, production continued at London Yard with Westwood and Baillie acting as managers for the London Engineering and Iron Ship Building Co. They regained nominal control of London Yard in 1872.

The company's notable works include the largest armour plate bending machine ever manufactured, erected at Pembroke Dockyard in 1872. They were the engineers and contractors of the Great Kei Bridge, Transki, South Africa in 1879 and in 1880 they built ironwork for Attock Bridge, Pakistan.

The company wound up in 1893.