William S. Monroe (March 16, 1878 – March 16, 1915) was an American infielder in baseball's Negro leagues. He was also known by the nickname of "Money." During a 19-year career from 1896 to 1914, he played on many of the greatest teams in black baseball. He was a good hitter and slick fielding third base and second baseman who was compared to major league star Jimmy Collins. Monroe played all four infield positions, but spent his prime seasons at third base and second base.