| Fighter | Record | Last Bout |
|---|---|---|
| Garreth McLellan | 13-6-0 | 2017-03-11 |
| Gegard Mousasi | 42-6-2 | 2017-04-08 |
| Gerald Meerschaert | 37-22-0 | 2026-05-02 |
| Gilbert Melendez | 22-8-0 | 2019-07-06 |
| Gina Mazany | 7-6-0 | 2022-04-30 |
| Glaico Franca Moreira | 15-5-0 | 2016-09-24 |
| Gray Maynard | 13-7-1 (1 NC) | 2018-10-06 |
| Guy Mezger | 30-14-2 | 1999-03-05 |
| Harry Moskowitz | 6-12-0 | 1998-05-15 |
| Henry Martinez | 9-4-0 | 2012-12-08 |
| Homer Moore | 26-9-2 | 2001-11-02 |
| Humberto Brown Morrison | 4-6-0 | 2014-11-15 |
| Ian Machado Garry | 17-2-0 | 2026-08-15 |
| Ian McCall | 13-5-1 | 2015-01-31 |
| Ikuhisa Minowa | 60-42-8 | 2000-04-14 |
| Islam Makhachev | 29-1-0 | 2026-08-15 |
| Ivan Menjivar | 25-12-0 | 2014-03-01 |
| Jack Della Maddalena | 18-4-0 | 2026-05-02 |
| Jack Marshman | 23-10-0 | 2020-10-31 |
| Jack May | 9-3-0 | 2014-08-16 |
| Jack McGlaughlin | 1-4-0 | 1995-07-14 |
| Jackson McVey | 8-2-0 | 2026-08-22 |
| Jacob Malkoun | 10-3-0 | 2026-05-02 |
| Jake Matthews | 23-8-0 | 2026-05-30 |
| James McSweeney | 15-15-0 | 2010-10-16 |
| James Moontasri | 9-5-0 | 2016-12-17 |
| James Mulheron | 11-2-0 | 2017-07-16 |
| Jamie Moyle | 4-3-0 | 2018-07-07 |
| Jamie Mullarkey | 18-9-0 | 2026-01-31 |
| Jason MacDonald | 25-16-0 | 2012-05-15 |
| Jason Miller | 23-10-0 (1 NC) | 2012-05-26 |
| Jean Matsumoto | 18-2-0 | 2026-06-27 |
| Jeff Molina | 11-2-0 | 2022-06-04 |
| Jeff Monson | 60-26-1 | 2006-11-18 |
| Jennifer Maia | 21-10-1 | 2023-10-14 |
| Jim Miller | 39-19-0 (1 NC) | 2026-05-09 |
| Jim Mullen | 0-2-0 | 1997-02-07 |
| Jimi Manuwa | 17-6-0 | 2019-06-01 |
| Joe Merritt | 7-2-0 | 2015-06-27 |
| Joe Moreira | 2-2-0 | 1997-07-27 |
| John Maguire | 24-9-0 | 2013-06-15 |
| John Makdessi | 18-9-0 | 2023-09-09 |
| John Marsh | 8-7-0 | 2005-04-16 |
| John Matua | 1-4-0 | 1995-07-14 |
| John Moraga | 19-7-0 | 2018-08-25 |
| Johnny Munoz | 12-4-0 | 2023-10-07 |
| Jon Madsen | 8-2-0 | 2011-03-26 |
| Jon Manley | 9-4-0 | 2013-02-23 |
| Jonathan Martinez | 19-6-0 | 2024-11-16 |
| Jonathan Meunier | 8-1-0 | 2016-11-26 |