The 2012–13 NBL season was the 35th season of competition since its establishment in 1979. A total of eight teams contested the league. The regular season was played between 5 October 2012 and 24 March 2013, followed by a post-season which involved the top four in April 2013. The schedule was announced on 4 June 2012. The New Zealand Breakers successfully defended their 2011–12 title for a third consecutive championship. Sponsorship included iiNet entering its third season as league naming rights sponsor and Spalding providing equipment including the official game ball.