The 1988–89 ACB season was the 6th season of the Liga ACB, after changing its name. The number of teams increased from 16 to 24. The format also changed. The 24 teams were divided into two groups of 12. After playing a league, 24 teams were divided into three groups of eight teams each. The first six of the white group and the champions of the red and blue groups played for the title. FC Barcelona won their third ACB title, and their 6th overall. It was their third ACB title in a row.