William Joseph Stewart (September 20, 1895 – February 18, 1964) was an American coach and sports official who was a referee in the National Hockey League (NHL) and an umpire in Major League Baseball (MLB). In 1938, as head coach of the Chicago Black Hawks, he led the team to a championship, becoming the first U.S.-born coach to win the Stanley Cup. He is an inductee of the United States Hockey Hall of Fame.