Lyle Dean MacWilliam (born 31 July 1949) was a New Democratic member of the House of Commons of Canada from 1988 to 1993, representing the constituency of Okanagan-Shuswap. Born in Vancouver, British Columbia, the son of John Michael MacWilliam and Doris Louise Coghill, MacWilliam studied at Simon Fraser University. In 1971, he married Arlene Leslie Sundvick.