John Leo Mokan (September 23, 1895 – February 10, 1985) was a Major League Baseball outfielder. He batted and threw right-handed. A native of Buffalo, New York, Mokan made his major league debut on April 15, 1921 at the age of 25. He spent seven seasons in the National League with the Pittsburgh Pirates (1921–22) and Philadelphia Phillies (1923–27). He died in Buffalo, New York at age 89.