The 2017 K League Classic was the 35th season of the top division of South Korean professional football since its establishment in 1983, and the fifth season of the K League Classic.

The exact matches are determined upon the league table at the time of the split.

The winner on aggregate score after both matches earned entry into the 2018 K League 1.

Sangju Sangmu won 5–4 on penalties and therefore both clubs remain in their respective leagues.

Source: K LeagueNotes:† Teams that played previous season in K League Challenge.