William James "Peg" Duval (August 3, 1877 – June 7, 1905) was a Canadian professional ice hockey defenceman who played for the Ottawa Hockey Club and the Pittsburgh Victorias in the late 1890s and early 1900s. He was a member of the Canadian champion 1901 Ottawa team and captain of the Ottawa team for the 1902 season. He was one of the first professional players in ice hockey.