Andrew Holger Olsen (November 30, 1930 - May 23, 2014) is a former professional baseball umpire who worked in the National League from 1968 to 1980, wearing uniform number 12 for most of his career. Olsen umpired 1,860 major league games in his 13-year career. He umpired in the 1974 World Series, three League Championship Series (1971, 1975, and 1978) and the 1976 Major League Baseball All-Star Game. Olsen also played in the minor leagues from to , as a pitcher.