| Competition: | KEB Hana Bank K League Challenge |
| Season: | 2017 |
| Winners: | Gyeongnam FC (1st title) |
| Promoted: | Gyeongnam FC |
| Best Player: | Marcão |
| League Topscorer: | Marcão (22 goals) |
| Matches: | 180 |
| Total Goals: | 454 |
| Biggest Home Win: | Bucheon 6–2 Anyang (19 June 2017) |
| Biggest Away Win: | Daejeon 1–4 Seongnam (27 August 2017) (2 September 2017) |
| Highest Scoring: | Bucheon 6–2 Anyang (19 June 2017) |
| Highest Attendance: | 10,683 Anyang 1–4 Gyeongnam (2 September 2017) |
| Average Attendance: | 2,324 |
| Prevseason: | 2016 |
| Nextseason: | 2018 |
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Withdrawn
| Ansan Greeners | FC Anyang | Asan Mugunghwa | Bucheon FC 1995 | Busan IPark | |
|---|---|---|---|---|---|
| Ansan Wa~ Stadium | Anyang Stadium | Yi Sun-sin Stadium | Bucheon Stadium | Busan Gudeok Stadium | |
| Capacity: 35,000 | Capacity: 17,143 | Capacity: 19,283 | Capacity: 34,545 | Capacity: 12,349 | |
| Daejeon Citizen | Gyeongnam FC | Seongnam FC | Seoul E-Land | Suwon FC | |
| Daejeon World Cup Stadium | Changwon Football Center | Tancheon Stadium | Seoul Olympic Stadium | Suwon Sports Complex | |
| Capacity: 40,535 | Capacity: 15,500 | Capacity: 16,146 | Capacity: 69,950 | Capacity: 11,808 | |
Note: Flags indicate national team as has been defined under FIFA eligibility rules. Players may hold more than one non-FIFA nationality.
| Team | Managers | Kit manufacturer | Main sponsor | |
|---|---|---|---|---|
| Ansan Greeners | Lee Heung-sil | Kelme | Ansan Government | |
| FC Anyang | Kim Jong-pil | Astore | Anyang Government | |
| Asan Mugunghwa | Song Sun-ho | Puma | Asan Government | |
| Bucheon FC 1995 | Jeong Gab-seok | Astore | Bucheon Government | |
| Busan IPark | Cho Jin-ho | Adidas | Hyundai Development Company | |
| Daejeon Citizen | Lee Young-ik | Astore | Daejeon Government | |
| Gyeongnam FC |  Kim Jong-boo | Hummel | Gyeongnam Government | |
| Seongnam FC | Park Kyung-hoon | Umbro | Seongnam Government | |
| Seoul E-Land | Kim Byung-soo | New Balance | E-Land | |
| Suwon FC | Cho Duck-je | Hummel | Suwon Government |
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.
| Club | Player 1 | Player 2 | Player 3 | Asian Player | |
|---|---|---|---|---|---|
| Ansan Greeners |  Luka Rotković |  Raúl Tarragona |  Bahodir Nasimov | ||
| FC Anyang |  Jô | Lukian | Aubin Kouakou | ||
| Bucheon FC 1995 | Nilson Júnior | Waguininho | Rodrigo Paraná | Bakhodir Pardayev | |
| Busan IPark | Danny Morais | Rômulo | Léo Mineiro |  Michihiro Yasuda | |
| Daejeon Citizen | Bruno Cantanhede |  Levan Shengelia |  Cristian Dănălache | ||
| Gyeongnam FC | Marcão | Ivan Herceg | |||
| Dário Júnior | Marin Oršulić | ||||
| Wesley Alex | Daniel Lovinho | Tomoki Wada | Atsuki Wada | ||
| Suwon FC |  Bruce Djite | Pedro Carmona | Vladan Adžić | Adrian Leijer |
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.
-----1–1 on aggregate. Sangju Sangmu won 5–4 on penalties and therefore both clubs remain in their respective leagues.
| Rank | Player | Club | Goals | ||
|---|---|---|---|---|---|
| 1 | Marcão | Gyeongnam FC | 22 | ||
| 2 | Raúl Tarragona | Ansan Greeners | 15 | ||
| 3 | Waguininho | Bucheon FC 1995 | 12 | ||
| 4 | Jung Won-jin | Gyeongnam FC | 10 | ||
| align=center rowspan=5 | 5 | Ko Kyung-min | Busan IPark | align=center rowspan=5 | 9 |
| Lee Jeong-hyeop | Busan IPark | ||||
| Cristian Dănălache | Daejeon Citizen | ||||
| Park Sung-ho | Seongnam FC | ||||
| Jin Chang-soo | Bucheon FC 1995 | ||||
| align=center rowspan=2 | 10 | Baek Sung-dong | Suwon FC | align=center rowspan=2 | 8 |
| Jeong Jae-hee | FC Anyang |
| Rank | Player | Club | Assists | ||
|---|---|---|---|---|---|
| 1 | Chang Hyuk-jin | Ansan Greeners | 13 | ||
| 2 | Jung Won-jin | Gyeongnam FC | 10 | ||
| align=center rowspan=2 | 3 | Alex Bruno | Gyeongnam FC | align=center rowspan=2 | 8 |
| Kim Shin | Bucheon FC 1995 | ||||
| 5 | Atsuki Wada | Seoul E-Land FC | 7 | ||
| align=center rowspan=3 | 6 | Rômulo | Busan IPark | align=center rowspan=3 | 6 |
| Lee Ho-seok | Daejeon Citizen | ||||
| Kim Shin | Bucheon FC 1995 | ||||
| align=center rowspan=3 | 9 | Kim Bong-rae | Suwon FC | align=center rowspan=3 | 5 |
| Lee Ju-yong | Asan Mugunghwa | ||||
| Jeong Jae-hee | FC Anyang |
Attendants who entered with free ticket were not counted.
The 2016 K League Awards was held on 20 November 2017.[1]
Marcão (Gyeongnam FC)
Marcão (Gyeongnam FC)
Chang Hyuk-jin (Ansan Greeners)
| Position | Player | Club |
|---|---|---|
| Goalkeeper | Lee Bum-soo | Gyeongnam FC |
| Defenders | Choi Jae-soo | Gyeongnam FC |
| Park Ji-soo | Gyeongnam FC | |
| Ivan Herceg | Gyeongnam FC | |
| Woo Joo-sung | Gyeongnam FC | |
| Midfielders | Jung Won-jin | Gyeongnam FC |
| Hwang In-beom | Daejeon Citizen | |
| Moon Ki-han | Bucheon FC 1995 | |
| Bae Ki-jong | Gyeongnam FC | |
| Forwards | Marcão | Gyeongnam FC |
| Lee Jeong-hyeop | Busan IPark |
| Month | Manager | Club | Division | |
|---|---|---|---|---|
| March | Jo Sung-hwan | Jeju United | K League Classic | |
| April | Kim Jong-boo | Gyeongnam FC | K League Challenge | |
| May | Choi Yun-kyum | Gangwon FC | K League Classic | |
| June | Choi Kang-hee | Jeonbuk Hyundai Motors | K League Classic | |
| July | Seo Jung-won | Suwon Samsung Bluewings | K League Classic | |
| August | Hwang Sun-hong | FC Seoul | K League Classic | |
| September | Kim Do-hoon | Ulsan Hyundai | K League Classic | |
| October | André | Daegu FC | K League Classic |