Duncan McKechnie (originally Duncan McGeachy) (1 May 1831 – 7 December 1913) was a British chemical manufacturer and metal extractor. He was trained as a soap boiler in Glasgow and later moved to become a foreman at a soap and alkali factory in Runcorn, Cheshire. In 1869 he entered into partnership with two colleagues to run a new chemical factory in the town, but soon left to found his own company in St Helens. This company specialised in extracting and refining metals. It was sold to the United Alkali Company in 1891. After McKechnie's retirement his descendants continued to run factories bearing the name McKechnie into the 20th century.