[4][5][6] The top six placed teams from the top-tier level Greek Basket League 2016–17 season, gained an automatic bye to the 2017–18 Greek Cup quarterfinals.

While the eight lower placed teams from the 2016–17 Greek Basket League season; along with all of the teams from the 2nd-tier level Greek A2 Basket League 2017–18 season, and the 3rd-tier level Greek B Basket League 2017–18 season, play in preliminary rounds, competing for the other two quarterfinals places.

The quarterfinals and onward rounds are played under a single elimination format.

Wednesday 2017-09-13 Note: Pierikos Archelaos decided to forfeit their game against Charilaos Trikoupis.

The other six sides were qualified based on their Greek Basket League 2016–17 season position.