| Competition: | Hyundai Oilbank K League Classic |
| Season: | 2015 |
| Winners: | Jeonbuk Hyundai Motors (4th title) |
| Continentalcup1: | Champions League |
| Continentalcup1 Qualifiers: | Jeonbuk Hyundai Motors FC Seoul Suwon Samsung Bluewings Pohang Steelers |
| Relegated: | Busan IPark Daejeon Citizen |
| Best Player: | Lee Dong-gook |
| League Topscorer: | Kim Shin-wook (18 goals) |
| Matches: | 228 |
| Total Goals: | 546 |
| Biggest Home Win: | Jeju 5–0 Daejeon (21 March 2015) |
| Biggest Away Win: | Daejeon 1–4 Seongnam (4 April 2015) |
| Highest Scoring: | Jeju 4–3 Seongnam (3 June 2015) Jeju 3–4 Suwon (17 June 2015) Daejeon 3–4 Jeonbuk (5 July 2015) Pohang 3–4 Jeju (8 July 2015) Jeonnam 2–5 Ulsan (25 October 2015) Seoul 3–4 Suwon (7 November 2015) |
| Longest Wins: | 6 matches Pohang Steelers |
| Longest Unbeaten: | 15 matches Pohang Steelers |
| Longest Winless: | 17 matches Daejeon Citizen |
| Longest Losses: | 8 matches Daejeon Citizen |
| Highest Attendance: | 39,328 Seoul 0–0 Suwon (27 June 2015) |
| Lowest Attendance: | 628 Jeonnam 2–1 Gwangju (7 November 2015) |
| Average Attendance: | 7,720 |
| Prevseason: | 2014 |
| Nextseason: | 2016 |
The 2015 K League Classic was the 33rd season of the top division of South Korean professional football, and the third season of the K League Classic.
| Busan IPark | Daejeon Citizen | Gwangju FC | Incheon United | Jeju United | Jeonbuk Hyundai Motors | |
|---|---|---|---|---|---|---|
| Busan Asiad Stadium | Daejeon World Cup Stadium | Gwangju World Cup Stadium | Incheon Football Stadium | Jeju World Cup Stadium | Jeonju World Cup Stadium | |
| Capacity: 53,864 | Capacity: 41,295 | Capacity: 44,118 | Capacity: 20,891 | Capacity: 35,657 | Capacity: 42,477 | |
| Jeonnam Dragons | Pohang Steelers | Seongnam FC | FC Seoul | Suwon Samsung Bluewings | Ulsan Hyundai | |
| Gwangyang Football Stadium | Pohang Steel Yard | Tancheon Stadium | Seoul World Cup Stadium | Suwon World Cup Stadium | Ulsan Munsu Football Stadium | |
| Capacity: 20,009 | Capacity: 25,000 | Capacity: 16,250 | Capacity: 66,704 | Capacity: 43,959 | Capacity: 44,474 | |
| Team | Outgoing | Manner | Date | Incoming | Date | Table |
|---|---|---|---|---|---|---|
| Jeonnam Dragons |  Ha Seok-ju | Resigned | 29 November 2014 | Roh Sang-rae | 29 November 2014 | Pre-season |
| Ulsan Hyundai | Cho Min-kook | Sacked | 1 December 2014 | Yoon Jung-hwan | 1 December 2014 | |
| Jeju United | Park Kyung-hoon | Resigned | 3 December 2014 | Jo Sung-hwan | 12 December 2014 | |
| Incheon United | Kim Bong-gil | Sacked | 19 December 2014 | Kim Do-hoon | 13 January 2015 | |
| Gwangju FC | Nam Ki-il (caretaker) | Promoted | 4 January 2015 | Nam Ki-il | 4 January 2015 | |
| Daejeon Citizen | Cho Jin-ho | Resigned | 21 May 2015 |  Michael Kim (caretaker) | 21 May 2015 | 12th |
| Daejeon Citizen | Michael Kim (caretaker) | Resigned | 26 May 2015 | Choi Moon-sik | 27 May 2015 | 12th |
| Busan IPark | Yoon Sung-hyo | Resigned | 13 July 2015 | Denis Iwamura (caretaker) | 13 July 2015 | 11th |
| Busan IPark | Denis Iwamura (caretaker) | Caretaker | 7 October 2015 | Choi Young-jun | 7 October 2015 | 11th |
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 including a least one player from the AFC country. Players name in bold indicates the player is registered during the mid-season transfer window.
Teams play each other twice, once at home, once away.
After 33 matches, the league splits into two sections of six teams each, with teams playing every other team in their section once (either at home or away). The exact matches are determined upon the league table at the time of the split.
The promotion-relegation play-offs were held between the winners of the 2015 K League Challenge play-offs 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 | Kim Shin-wook | Ulsan Hyundai | 18 | |
| 2 |  Adriano | Daejeon Citizen FC Seoul | align=center rowspan=2 | 15 |
| Hwang Ui-jo | Seongnam FC | |||
| 4 | Lee Dong-gook | Jeonbuk Hyundai Motors | 13 | |
| 5 | Júnior Santos | Suwon Samsung Bluewings | align=center rowspan=3 | 12 |
| Lee Jong-ho | Jeonnam Dragons | |||
 Stevica Ristić | Jeonnam Dragons | |||
| 8 | Edu | Jeonbuk Hyundai Motors | align=center rowspan=2 | 11 |
| Ricardo Lopes | Jeju United | |||
| 10 | Kwon Chang-hoon | Suwon Samsung Bluewings | align=center rowspan=2 | 10 |
| Leonardo | Jeonbuk Hyundai Motors |
| Rank | Player | Club | Assists | |
|---|---|---|---|---|
| 1 | Yeom Ki-hun | Suwon Samsung Bluewings | 17 | |
| 2 | Ricardo Lopes | Jeju United | align=center rowspan=2 | 11 |
 Mauricio Molina | FC Seoul | |||
| 4 | Kim Do-heon | Seongnam FC | 8 | |
| 5 | Mislav Oršić | Jeonnam Dragons | align=center rowspan=3 | 7 |
| Kim Tae-hwan | Ulsan Hyundai | |||
| Yoon Bit-garam | Jeju United | |||
| 8 | Ivan Kovačec | Ulsan Hyundai | align=center rowspan=3 | 6 |
| Song Jin-hyung | Jeju United | |||
| Ju Se-jong | Busan IPark |
The 2015 K League Awards was held on 1 December 2015.
[2]Attendants who entered with free ticket are not counted.
| Rank | Date | Home | Score | Away | Venue | Attendance | Round | Day of week | |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 27 June 2015 | 0–0 | 39,328 | 18 | Saturday | ||||
| 2 | 14 March 2015 | 1–2 | 32,516 | 2 | Saturday | ||||
| 3 | 26 July 2015 | 2–1 | 31,192 | 23 | Sunday | ||||
| 4 | 2 May 2015 | 2–0 | 30,410 | 9 | Saturday | ||||
| 5 | 19 September 2015 | 0–3 | 29,046 | 31 | Saturday | ||||
| 6 | 21 November 2015 | 1–1 | 28,460 | 37 | Saturday | ||||
| 7 | 12 September 2015 | 3–0 | 26,433 | 30 | Saturday | ||||
| 8 | 18 April 2015 | 5–1 | 26,250 | 7 | Saturday | ||||
| 9 | 25 October 2015 | 0–0 | 24,262 | 35 | Sunday | ||||
| 10 | 7 March 2015 | 2–0 | 23,810 | 1 | Saturday |
