The 1979–80 NBA season was the SuperSonics' 13th season in the NBA. The SuperSonics entered the season as the defending NBA champions, having defeated the Washington Bullets in five games in the 1979 NBA Finals, winning their first and only NBA championship. In the playoffs, the SuperSonics defeated the Portland Trail Blazers in three games in the First Round, then defeated the Milwaukee Bucks in seven games in the Semi-finals, before losing to the eventual NBA champion Los Angeles Lakers in five games in the Conference Finals.