The 1980–81 NBA season was the 35th season of the National Basketball Association. The season ended with the Boston Celtics winning the NBA Championship, beating the Houston Rockets 4 games to 2 in the NBA Finals.
* The Dallas Mavericks become the league's 23rd franchise. As a result, the NBA realigns four of its teams to better reflect their geographical locations (the Milwaukee Bucks and Chicago Bulls move to the Eastern Conference and the San Antonio Spurs and Houston Rockets to the Western Conference).
* The 1981 NBA All-Star Game was played at the Richfield Coliseum near Cleveland, Ohio, with the East defeating the West 123–120. Nate Archibald of the Boston Celtics wins the game's MVP award.
* To date, this was the final time that a regular-season had ended during the month of March.
* The Houston Rockets (40–42) become just the second team in NBA history (to date) to make the finals without posting a winning record during the regular season. The Kansas City Kings, their opponents in the Western Conference Finals, also posted a 40–42 record.