Marion Danne "Bill" Adair (February 10, 1913 – June 17, 2002) was an American coach and interim manager in Major League Baseball (MLB).

A second baseman, he was a career minor-league player who never rose about the Class AA level but who spent 21 years as a manager in the minors.

Born in Mobile, Alabama, Adair was a manager in the Braves organization (he managed farm clubs for all three cities the Braves played in), as well as the Detroit Tigers, San Diego Padres, Montreal Expos, and the Chicago White Sox organizations.

He compiled a 1,611-1,305 (.552) record in the minors, but his managing career in the major leagues was limited to ten games with the 1970 White Sox which was en route to a then franchise-worst 56–106 finish.

He had succeeded Don Gutteridge on an interim basis on September 2 with the team's record a major league-worst 49–87.