Tous les combattants
 | Oumar Kane | 1-0-0 REC | #2919 |  |
 | Oumar Sy | 3-2-0 UFC | #443 |  |
 | Ourouzmag Magkeyev | 0-1-0 REC | #4362 | |
 | Ousmane Camara | 1-0-0 REC | #1179 | |
 | Ovidio Bojorquez | 0-1-0 REC | #6899 |  |
 | Ovince St. Preux | 15-13-0 UFC | #279 |  |
 | Owain Williams | 0-1-0 REC | #7017 |  |
 | Owen Jason | 1-0-0 REC | #7787 | |
 | Oyatullo Muminov | 2-1-0 REC | #1014 |  |
 | Ozan Aslaner | 3-2-0 REC | #1062 |  |
 | Ozzy Diaz | 1-2-0 UFC | #1369 | |
| Pablo David | 0-1-0 REC | #7788 | |
 | Pablo dos Santos | #7741 |  | |
 | Pablo Garza | 3-3-0 UFC | #3167 | |
| Pablo Radjabou | 1-0-0 REC | #7810 | |
 | Paddy Holohan | 3-2-0 UFC | #3126 |  |
 | Paddy McCorry | 6-0-0 REC | #723 | |
 | Paddy Pimblett | 7-1-0 UFC | #54 |  |
| Paddy Rutledge | 1-0-0 REC | #1650 |  |
 | Paddy Wilkinson | 0-1-0 REC | #6510 | |
 | Paige VanZant | 5-4-0 UFC | #1733 | |
 | Pam Sorenson | 0-2-0 REC | #5332 | |
 | Pamela Boveda | 0-1-0 REC | #6603 |  |
 | Pamela Mara | 0-1-0 REC | #7536 | |
 | Panagiotis Stroumpoulis | 0-2-0 REC | #6849 |  |