John J. "Jack" Clements (July 24, 1864 – May 23, 1941) was a baseball player who played for 17 seasons in the Major Leagues. A catcher for nearly his entire career, despite being left-handed, Clements caught 1,073 games, almost four times as many as any other left-handed player in major league history and was the last left-hander to catch on a regular basis.