William Henry Mills Jr. (November 2, 1919 – August 9, 2019), also known as "Buster", was a catcher who played in Major League Baseball during the 1944 season. Listed at 5 ft 10 in (1.78 m), 175 lb (79 kg), he batted and threw right-handed. Born in Boston, Massachusetts, Mills was one of many ballplayers who appeared in the major leagues only during the World War II years.