| Fighter | Record | Last Bout |
|---|---|---|
| Alan Jouban | 17-7-0 | 2020-11-21 |
| Allen Frye Jr. | 6-1-0 | 2025-12-13 |
| Anshul Jubli | 7-2-0 | 2025-02-08 |
| Anthony Johnson | 22-6-0 | 2017-04-08 |
| Antonio Carlos Junior | 11-5-0 (1 NC) | 2021-01-23 |
| Baergeng Jieleyisi | 18-7-0 | 2024-11-23 |
| Ben Johnston | 5-2-0 | 2026-05-02 |
| Brandon Jenkins | 15-9-0 | 2022-04-16 |
| Brett Johns | 17-2-0 | 2020-07-18 |
| Brian Johnston | 5-5-0 | 1997-07-27 |
| Brock Jardine | 12-6-0 | 2013-02-23 |
| Carli Judice | 7-2-0 | 2026-08-22 |
| Carlo Pedersoli Jr. | 11-3-0 | 2019-02-23 |
| Carls John De Tomas | 6-2-0 | 2017-12-09 |
| Chan Sung Jung | 17-8-0 | 2023-08-26 |
| Chan-Mi Jeon | 5-2-0 | 2017-09-22 |
| Charles Johnson | 20-9-0 | 2026-08-15 |
| Charles Jourdain | 18-8-1 | 2026-09-19 |
| Cristiane Justino | 21-2-0 (1 NC) | 2019-07-27 |
| Da Woon Jung | 15-6-1 | 2024-09-28 |
| DaMarques Johnson | 15-15-0 | 2012-09-29 |
| Damon Jackson | 23-8-1 (1 NC) | 2024-11-16 |
| Daniel Jolly | 5-3-0 | 2017-02-04 |
| Dashon Johnson | 9-2-0 | 2014-09-13 |
| Demetrious Johnson | 27-3-1 | 2018-08-04 |
| Donte Johnson | 9-0-0 | 2026-08-15 |
| Dustin Jacoby | 22-10-1 | 2026-07-25 |
| Eugene Jackson | 15-9-1 | 2002-07-13 |
| Ivan Jorge | 27-7-0 | 2015-07-18 |
| Jacare Souza | 26-10-0 (1 NC) | 2021-05-15 |
| Jack Della Maddalena | 18-4-0 | 2026-05-02 |
| Jack Hermansson | 24-10-0 | 2025-11-22 |
| Jack Jenkins | 14-5-0 | 2026-08-29 |
| Jack Marshman | 23-10-0 | 2020-10-31 |
| Jack May | 9-3-0 | 2014-08-16 |
| Jack McGlaughlin | 1-4-0 | 1995-07-14 |
| Jack Nilson | 2-6-0 | 1997-05-30 |
| Jack Shore | 17-3-0 | 2024-11-02 |
| Jackie Lee | 0-1-0 | 1997-02-07 |
| Jackson McVey | 8-2-0 | 2026-08-22 |
| Jacob Kilburn | 8-4-0 | 2021-01-16 |
| Jacob Malkoun | 10-3-0 | 2026-05-02 |
| Jacob Volkmann | 19-7-0 | 2013-02-02 |
| Jacobe Smith | 12-0-0 | 2026-02-21 |
| Jacqueline Cavalcanti | 10-2-0 | 2026-05-16 |
| Jafel Filho | 17-5-0 | 2026-04-25 |
| Jai Herbert | 14-6-1 | 2026-04-18 |
| Jailton Almeida | 22-5-0 | 2026-02-07 |
| Jairzinho Rozenstruik | 15-6-0 | 2025-02-01 |
| Jake Collier | 13-10-0 | 2023-09-23 |