| Competition: | Hyundai Oilbank K League Challenge |
| Season: | 2015 |
| Winners: | Sangju Sangmu (2nd title) |
| Promoted: | Sangju Sangmu Suwon FC |
| Best Player: | Johnathan |
| League Topscorer: | Johnathan (26 goals) |
| Matches: | 220 |
| Total Goals: | 593 |
| Biggest Home Win: | Gangwon 4–0 Bucheon (4 April 2015) Seoul E 4-0 Chungju (16 May 2015) Sangju 4–0 Chungju (13 June 2015) Daegu 5–1 Sangju (23 September 2015) |
| Biggest Away Win: | Goyang 0–5 Sangju (13 May 2015) |
| Highest Scoring: | Gangwon 4–4 Seoul E (22 November 2015) |
| Highest Attendance: | 20,157 Daegu 2–1 Gangwon (29 March 2015) |
| Lowest Attendance: | 249 Goyang 1–0 Gangwon (10 June 2015) |
| Average Attendance: | 1,606 |
| Prevseason: | 2014 |
| Nextseason: | 2016 |
The 2015 K League Challenge was the third season of the K League 2, the second-highest division in the South Korean football league system. Champions and winners of promotion playoffs could be promoted to the K League Classic.[1]
Relegated from K League Classic
Promoted to K League Classic
Newly joined
| Ansan Police | FC Anyang | Bucheon FC 1995 | |
|---|---|---|---|
| Ansan Wa~ Stadium | Anyang Stadium | Bucheon Stadium | |
| Capacity: 35,000 | Capacity: 17,143 | Capacity: 34,545 | |
| Chungju Hummel | Daegu FC | Gangwon FC | |
| Chungju Stadium | Daegu Stadium | Gangneung Stadium | |
| Capacity: 15,000 | Capacity: 68,014 | Capacity: 22,333 | |
| Goyang Hi FC | Gyeongnam FC | Sangju Sangmu | |
| Goyang Stadium | Changwon Football Center | Sangju Stadium | |
| Capacity: 41,311 | Capacity: 15,500 | Capacity: 15,042 | |
| Seoul E-Land | Suwon FC | ||
| Seoul Olympic Stadium | Suwon Stadium | ||
| Capacity: 69,950 | Capacity: 24,670 | ||
Note: Flags indicate national team as has been defined under FIFA eligibility rules. Players may hold more than one non-FIFA nationality.
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.
When the first round and semi-final match were finished as draws, their winners were decided on the regular season rankings without extra time and the penalty shoot-out.
The promotion-relegation playoffs were held between the winners of the 2015 K League Challenge playoffs and the 11th-placed club of the 2015 K League Classic. The winners on aggregate score after both matches earned entry into the 2016 K League Classic.
----Suwon FC won 3–0 on aggregate and were promoted to the K League Classic, while Busan IPark were relegated to the K League Challenge.
| Rank | Player | Club | Goals | ||
|---|---|---|---|---|---|
| 1 |  Johnathan | Daegu FC | 26 | ||
| 2 |  Joo Min-kyu | Seoul E-Land | 23 | ||
| align=center rowspan=2 | 3 | Japa | Suwon FC | align=center rowspan=2 | 19 |
| Cho Seok-jae | Chungju Hummel | ||||
| 5 | Tarabai | Seoul E-Land | 17 | ||
| 6 | Ko Kyung-min | FC Anyang | 16 | ||
| 7 | Jonatas Belusso | Gangwon FC | 15 | ||
| align=center rowspan=2 | 8 | Lim Sang-hyub | Sangju Sangmu | align=center rowspan=2 | 12 |
| Kim You-sung | Goyang Hi FC | ||||
| align=center rowspan=2 | 10 | Choi Seung-in | Gangwon FC | align=center rowspan=2 | 11 |
| Rodrigo Paraná | Bucheon FC 1995 |
| Rank | Player | Club | Assists | ||
|---|---|---|---|---|---|
| 1 | Kim Jae-sung | Seoul E-Land | 11 | ||
| align=center rowspan=3 | 2 | Lim Chang-gyoon | Gyeongnam FC | align=center rowspan=3 | 9 |
| Seo Bo-min | Gangwon FC | ||||
| Moon Ki-han | Daegu FC | ||||
| 5 | Kim Jong-woo | Suwon FC | 8 | ||
| align=center rowspan=4 | 6 | Jang Baek-gyu | Daegu FC | align=center rowspan=4 | 7 |
| Japa | Suwon FC | ||||
| Choi Jin-soo | FC Anyang | ||||
| Joo Min-kyu | Seoul E-Land | ||||
| align=center rowspan=7 | 10 | Lee Jung-hyup | Sangju Sangmu | align=center rowspan=7 | 6 |
| Han Sang-woon | Sangju Sangmu | ||||
| Kim Young-keun | Seoul E-Land | ||||
| Kwon Yong-hyun | Suwon FC | ||||
| Lee Hak-min | Bucheon FC 1995 | ||||
| Jin Chang-soo | Goyang Hi FC | ||||
| Johnathan | Daegu FC |
Attendants who entered with free ticket were not counted.
The 2015 K League Awards was held on 1 December 2015.[2]
| Position | Player | Club |
|---|---|---|
| Goalkeeper | Jo Hyeon-woo | Daegu FC |
| Defenders | Park Jin-po | Sangju Sangmu |
| Shin Hyung-min | Ansan Police | |
| Kang Min-soo | Sangju Sangmu | |
| Lee Yong | Sangju Sangmu | |
| Midfielders | Ko Kyung-min | FC Anyang |
| Lee Seung-gi | Sangju Sangmu | |
| Cho Won-hee | Seoul E-Land | |
| Kim Jae-sung | Seoul E-Land | |
| Forwards | Johnathan | Daegu FC |
| Joo Min-kyu | Seoul E-Land |
