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| Season | 2021 |
|---|---|
| Dates | 27 February – 5 December 2021 |
| Champions | Jeonbuk Hyundai Motors (9th title) |
| Relegated | Gwangju FC |
| Champions League | Jeonbuk Hyundai Motors Ulsan Hyundai Daegu FC |
| Matches played | 228 |
| Goals scored | 563 (2.47 per match) |
| Best Player | Hong Jeong-ho |
| Top goalscorer | Joo Min-kyu (22 goals) |
| Biggest home win | Ulsan 5–0 Gangwon (1 March 2021) |
| Biggest away win | Daegu 0–5 Jeju (31 October 2021) |
| Highest scoring | Seoul 3–4 Jeonbuk (5 September 2021) |
| Highest attendance | 6,199 |
| Lowest attendance | 1,218 |
← 2020 2022 → | |
The 2021 K League 1, also known as the Hana 1Q K League 1 for sponsorship reasons, was the 39th season of the top division of professional football in South Korea, and the ninth season of the K League 1. Jeonbuk Hyundai Motors won their ninth title and fifth consecutive title.
After progressing 33 regular rounds, the league was divided into two groups, the top six and the bottom six, and each team played five matches against other teams in its group.