Bolckow, Vaughan & Co., Ltd was an English ironmaking and mining company founded in 1864, based on the partnership since 1840 of its two founders, Henry Bolckow and John Vaughan. The firm drove the dramatic growth of Middlesbrough and the production of coal and iron in the north-east of England in the 19th century. The two founding partners had an exceptionally close working relationship which lasted until Vaughan's death. By 1907 Bolckow, Vaughan was possibly the largest producer of pig iron in the world. The firm failed to modernise at the start of the 20th century, and was closed in 1929.