2023–24 Boston Celtics season

The 2023–24 Boston Celtics season was the franchise's 78th season in the National Basketball Association (NBA). After the Pittsburgh Penguins of the National Hockey League (NHL) missed the playoffs for the first time in 17 years, the Celtics entered the season in second place behind the Los Angeles Dodgers of Major League Baseball (MLB) for the longest active playoffs streak in major North American sports at nine years (having last missed the playoffs in 2014).

The Celtics had the best record (64–18) in the NBA and proceeded through the playoffs in dominant fashion. They defeated the Dallas Mavericks in five games during the NBA Finals, winning the franchise's first championship since 2008, and 18th championship in team history, breaking a tie with the Los Angeles Lakers to hold the NBA record for most championships. The result was the most dominant Celtics championship run since 1965, with only three losses in the playoffs and a season total of 80 wins, the second-best mark in franchise history.

Following their championship victory, multiple commentators considered the 2023–24 Celtics to be among the greatest teams in NBA history. With a playoff record of 16–3, the Celtics were second only to the 2016–17 Golden State Warriors for the best postseason record since all four NBA playoff rounds became best-of-seven contests in 2003.

The Celtics drew an average home attendance of 19,156 in 41 home games in the 2023–24 NBA season.