The 1963–64 NBA season was the Celtics' 18th season in the NBA. The Celtics finished the season by winning their seventh NBA Championship.
The Celtics were one of the dominant teams in the leagues. The team established its legacy as one of the game's greatest dynasties ever. 1950s superstar Bob Cousy had retired, yet Red Auerbach's club barely slowed down with his absence. Cousy's replacement was a defensive specialist named K. C. Jones, who continued Auerbach's emphasis on defense along with forward Tom 'Satch' Sanders and center Bill Russell. While Boston could surely still pass and score, it was their defensive emergence, led by the incredible Russell, that was now leading a streak of NBA titles. Russell led the league in rebounds and was one of two high-volume shot blockers dominating the NBA. The Celtics had six scorers over ten-points per game and two more over eight. Auerbach's sixth man, John Havlicek, was the team's leading scorer at 20 per game. This combination of active defense and unselfish shooting got Boston a league-high 59 wins in 80 NBA games.