On 15 May 2019, the Greek Basket League announced that it was planning to expand from 14 teams to 16 teams, and that there were no league relegations scheduled from the previous 2018–19 Greek Basket League season. The teams that were scheduled to be promoted up from the secondary level Greek A2 Basket League, were to be inserted into the new 16-team league, for the 2019–20 season. However, Olympiacos was later relegated on 22 May 2019, following a meeting of the Hellenic Basketball Clubs Association's Board of Directors.Olympiacos officially relegated to Second Division.
