The 1989 NBL season was the eighth season of the National Basketball League. Ponsonby's last-place finish in 1988 saw them dropped from the league and replaced by 1988 Conference Basketball League (CBL) champions Palmerston North. Canterbury won the championship in 1989 to claim their second league title. They came from fourth place at the finals weekend to claim the championship, knocking over the top-seeded Palmerston North 92–84 in the semi-finals, before defeating Auckland 91–83 in the final.