Douglas Marmaduke Caston (September 17, 1917 – June 26, 1996) was a newspaper publisher and served as a Canadian federal politician from 1967 until 1968.Caston ran for a seat in the Canadian House of Commons in a by-election on November 6, 1967. He defeated Liberal candidate Allen Sulatycky to win the Jasper—Edson riding. Parliament would be dissolved a year later and Caston ran for re-election in the new Rocky Mountain electoral district as Jasper—Edson was abolished.