John Curtis "Jack" Chapman (May 8, 1843 – June 10, 1916) was an American Major League Baseball player and manager who was born in Brooklyn, New York. He began playing in the National Association when he played for the 1874 Brooklyn Atlantics and the 1875 St. Louis Brown Stockings. In 1876, when the National League formed, he became the player-manager for the Louisville Grays. The following season saw him staying with Louisville in the manager role only. After the 1877 season, the Louisville team was expelled from the National League, and Chapman became manager of the Milwaukee Grays. The team had a poor record, and he was fired.