2003–04 Boston Celtics season

The 2003–04 Boston Celtics season was the 58th season of the Boston Celtics in the National Basketball Association (NBA). During the offseason, the Celtics acquired Raef LaFrentz from the Dallas Mavericks. The Celtics roster move continued in December when Tony Battie and Eric Williams were both traded to the Cleveland Cavaliers for Ricky Davis. In February, Mike James was traded to the Detroit Pistons for Lindsey Hunter and Chucky Atkins in a three-team trade involving the Atlanta Hawks. However, Hunter was waived after the trade and later re-signed with the Pistons. The team also released Vin Baker, who went off to sign with the New York Knicks.

Celtics head coach Jim O'Brien resigned after a slow start to the season. He was replaced by John Carroll for the rest of the season. When General Manager Danny Ainge stated that the Celtics would be better off missing the playoffs, the statement seemed to motivate the team as they posted a 9–5 record in March. The Celtics, despite finishing fourth in the Atlantic Division with a low 36–46 record, qualified for the playoffs as the number 8 seed. They were swept in four games by the Indiana Pacers in the opening round.