The 2021 NBL season was the 40th season of the National Basketball League. As a result of the modified, COVID-affected 2020 season, three of the top four teams in 2019 (Wellington Saints, Hawke's Bay Hawks and Southland Sharks) did not compete. All three teams re-entered in 2021 to increase the league's total number to 10 for the first time since 2014.