George Harold Sisler Jr. (August 1, 1917 – December 31, 2006) was an American professional baseball player and executive. The son of Hall of Fame first baseman and two-time .400 hitter George Sisler and the brother of two Major League Baseball players, Dick and Dave, George Jr. was a longtime executive in minor league baseball, especially in the Triple-A International League (IL); at his death, the IL calculated that Sisler had been associated with that league for 52 of its 124 years of existence. He also served in the majors as chief assistant to St. Louis Cardinals vice president and de facto general manager William Walsingham Jr. during the late 1940s and early 1950s.