John William Flater (September 22, 1883 – March 20, 1970) was a Major League Baseball pitcher for the Philadelphia Athletics just at the end of the 1908 season (September 18 – October 3). The 5 ft 10 in (1.78 m), 175 lb. right-hander was a native of Sandymount, Maryland. Four of his famous teammates on the Athletics were future Hall of Famers Chief Bender, Eddie Collins, Jimmy Collins, and Eddie Plank. Flater died at the age of 87 in Westminster, Maryland, and is buried in nearby Sandymount, Maryland.