Alex Kellner, American baseball player (b. 1924)
Alexander Raymond Kellner (August 26, 1924 – May 3, 1996) was an American starting pitcher in Major League Baseball who played for the Philadelphia / Kansas City Athletics (1948–1958), Cincinnati Reds (1958) and St. Louis Cardinals (1959). Kellner batted right-handed and threw left-handed. He was born in Tucson, Arizona. His younger brother, Walt, also was a major league pitcher.

In a 12-season career, Kellner posted a 101–112 record with 816 strikeouts and a 4.17 ERA in 1,849+1⁄3 innings pitched. He won 20 games for the Athletics in 1949.

Kellner died in Tucson, Arizona, at the age of 71.