| Fighter | Record | Last Bout |
|---|---|---|
| Josh Shockman | 6-3-0 | 2006-11-18 |
| Josh Stansbury | 4-8-0 | 2017-06-25 |
| Josh Stuart | 1-4-0 | 1998-03-13 |
| Josh Thomson | 22-9-0 (1 NC) | 2015-07-15 |
| Joshua Burkman | 28-16-0 (1 NC) | 2018-02-18 |
| Joshua Van | 17-2-0 | 2026-09-19 |
| Joshua Weems | 11-3-0 | 2022-10-29 |
| Josiah Harrell | 11-1-0 | 2026-09-26 |
| Josiane Nunes | 10-4-0 | 2025-03-15 |
| Josias Musasa | 8-2-0 | 2025-09-27 |
| Journey Newson | 10-5-0 (1 NC) | 2023-04-29 |
| Jovan Leka | 14-2-0 | 2026-08-01 |
| Juan Adams | 5-3-0 | 2020-02-08 |
| Juan Diaz | 16-1-1 | 2026-05-16 |
| Juan Espino | 11-2-0 | 2021-04-17 |
| Juan Manuel Puig | 11-4-0 | 2014-11-22 |
| Juancamilo Ronderos | 4-2-0 | 2023-02-18 |
| Jules Bruchez | 1-2-0 | 2008-12-13 |
| Julia Avila | 9-4-0 | 2025-02-15 |
| Julia Polastri | 15-6-0 | 2026-08-29 |
| Julian Erosa | 31-14-0 | 2026-03-28 |
| Julian Marquez | 9-6-0 | 2025-03-01 |
| Julian Sanchez | 0-1-0 | 1996-09-20 |
| Juliana Lima | 9-5-0 | 2018-01-27 |
| Juliana Miller | 6-4-0 | 2026-08-08 |
| Julianna Pena | 13-6-0 | 2025-06-07 |
| Julie Kedzie | 16-13-0 | 2013-12-06 |
| Julien Leblanc | 10-3-0 | 2026-10-17 |
| Julija Stoliarenko | 11-10-2 | 2025-08-09 |
| Julio Arce | 19-6-0 | 2024-03-30 |
| Julio Paulino | 23-5-0 | 2010-09-25 |
| Julius Walker | 7-3-0 | 2026-06-27 |
| Jumabieke Tuerxun | 19-4-1 | 2014-11-07 |
| JunYong Park | 19-7-0 | 2025-10-25 |
| Junie Browning | 5-6-0 | 2009-04-01 |
| Junior Albini | 14-6-0 | 2019-06-29 |
| Junior Assuncao | 16-6-0 | 2011-12-30 |
| Junior Dos Santos | 21-9-0 | 2020-12-12 |
| Junior Tafa | 7-6-0 | 2026-06-06 |
| Jussier Formiga | 23-8-0 | 2020-06-06 |
| Justin Buchholz | 15-10-0 | 2010-02-06 |
| Justin Edwards | 9-5-0 | 2015-06-06 |
| Justin Eilers | 19-7-1 | 2006-02-04 |
| Justin Frazier | 10-3-0 | 2018-11-30 |
| Justin Gaethje | 28-5-0 | 2026-06-14 |
| Justin James | 13-7-0 | 2006-10-14 |
| Justin Jaynes | 16-8-0 | 2021-06-26 |
| Justin Jones | 9-2-0 | 2015-04-04 |
| Justin Lawrence | 10-4-0 | 2013-04-13 |
| Justin Ledet | 9-4-0 (1 NC) | 2020-10-31 |