Top KBO Players by Earned Run Average in 2021
| # | Player | Team | ERA | IP |
|---|---|---|---|---|
| 1 | Doosan | 2.33 | 173 ⅔ | |
| 2 | Samsung | 2.63 | 157 ⅔ | |
| 3 | KT | 2.92 | 166 ⅔ | |
| 4 | Kiwoom | 2.93 | 181 ⅓ | |
| 5 | Samsung | 3.06 | 158 ⅔ | |
| 6 | Samsung | 3.10 | 177 | |
| 7 | LG | 3.15 | 177 | |
| 8 | NC | 3.17 | 178 ⅔ | |
| 9 | Hanwha | 3.19 | 144 | |
| 10 | Doosan | 3.30 | 158 ⅓ | |
| 11 | KT | 3.39 | 188 ⅔ | |
| 12 | SSG | 3.46 | 145 ⅔ | |
| 13 | Hanwha | 3.97 | 170 | |
| 14 | Lotte | 3.98 | 163 | |
| 15 | Hanwha | 4.00 | 155 ⅓ | |
| 16 | Lotte | 4.07 | 165 ⅔ | |
| 17 | NC | 4.41 | 145 | |
| 18 | Kia | 4.88 | 153 | |
| 19 | Lotte | 5.40 | 150 |