The 2017 K League Challenge was the fifth season of the K League 2, the second-highest division in the South Korean football league system. Champions and winners of the promotion playoffs could be promoted to the K League 1.
Relegated from K League Classic
Promoted to K League Classic
Newly joined
Withdrawn
<small>Note: Flags indicate national team as has been defined under FIFA eligibility rules. Players may hold more than one non-FIFA nationality.</small>
Restricting the number of foreign players strictly to four per team, including a slot for a player from AFC countries. A team could use four foreign players on the field each game.
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The promotion-relegation playoffs were held between the winners of the 2017 K League Challenge playoffs and the 11th-placed club of the 2017 K League Classic. The winner on aggregate score after both matches earned entry into the 2018 K League 1.
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1âÂÂ1 on aggregate. Sangju Sangmu won 5âÂÂ4 on penalties and therefore both clubs remain in their respective leagues.
Attendants who entered with free ticket were not counted.
The 2016 K League Awards was held on 20 November 2017.