William Henry McClellan (March 22, 1856 – July 3, 1929) was an American Major League Baseball player for eight seasons, and primarily played as a second baseman and shortstop from 1878 to 1888. Born in Chicago, McClellan played one season for the St. Paul Red Caps of the League Alliance in 1877. He appeared with the Chicago White Stockings of the National League in 1878, then with the Washington Nationals of the Nationals of the National Association in 1879 and 1880. McClellan returned to the National League and the American Association after that, and he led the league in games played in 1885 (112) and 1886 (141) with the Brooklyn Grays.