John Bertrand "Jocko" Conlan (December 6, 1899 – April 16, 1989) was an American baseball umpire who worked in the National League (NL) from 1941 to 1965.
He had a brief career as an outfielder with the Chicago White Sox before entering umpiring.
He umpired in five World Series and six All-Star Games.
He was elected to the Baseball Hall of Fame in 1974 by the Veterans Committee.