William Charles Lachemann (born April 5, 1934 at Los Angeles) is an American professional baseball coach. A longtime member of the Los Angeles Angels of Anaheim organization, in 2018 at age 84 he was still active in professional baseball as the Angel organization's roving catching instructor. He is the eldest brother of three siblings who have had long careers in the game: Marcel and Rene have been players, managers and coaches in Major League Baseball and also remain active in the game. In 1995 and 1996, Bill Lachemann served as bullpen coach on the staff of his brother Marcel, then skipper of the Angels.