The 2017–18 Gamma Ethniki was the 35th season since the official establishment of the third tier of Greek football in 1983.
After matches were completed in the eight groups, the top team in each group qualified for a playoff round of two groups,[1] to determine which four teams would be promoted to the Football League.
97 teams were divided into eight groups according to geographical criteria.
[2][3] Panelefsiniakos, AO Chania, AEL Kalloni, Panthrakikos, Eordaikos, A.E.
Istiaia, Mavroi Aetoi Eleftherochori, Amvrakia Kostakioi, APO Kanaris Nenita, Pyrsos Grevena, AO Syros, Poseidon Neoi Poroi and AO Polykratis Pythagoreio[4] withdrew from the league before the group draw.