John Emil Jaha (born May 27, 1966) is a former first baseman in Major League Baseball who had a 10-year career from 1992 to 2001. He played for the Milwaukee Brewers and Oakland Athletics, playing in both the American League and National League. He was elected to the American League All-Star team in 1999. Jaha graduated from David Douglas High School in Portland, Oregon, in 1984. He still holds most offensive baseball records for the school.