William Lamar "Billy" Beane III (born March 29, 1962) is a former American professional baseball player and current front office executive. He is the general manager (GM) and minority owner of the Oakland Athletics of Major League Baseball (MLB). Prior to his front office career, he played in MLB as an outfielder between 1984 and 1989 for the New York Mets, Minnesota Twins, Detroit Tigers, and Oakland Athletics. He joined the Athletics' front office as a scout in 1990, and was named GM after the 1997 season.

A first round pick in the MLB draft by the Mets, Beane's playing career failed to meet the expectations of the scouts, who projected him as a star. In his front office career, Beane has applied statistical analysis to players, known as sabermetrics, which has led all teams to reconsider how they evaluate players. He is the subject of Michael Lewis' 2003 book on baseball economics, Moneyball, which was made into a 2011 film starring Brad Pitt as Beane.