Fighters — O
25 tracked fighters starting with O.
- Oban Elliott 12-4-0 · Welterweight · UFC
- Ode Osbourne 13-9-0 · Flyweight · UFC
- Olaf Alfonso 8-12-0 · Lightweight · TPF
- Oleg Taktarov 17-5-2 · Heavyweight ·
- Oleksandr Usyk 25-0-0 · heavyweight · Boxing
- Oli Thompson 22-16-0 · Light Heavyweight · GOR MMA
- Oliver Enkamp 11-4-0 · Welterweight · Bellator MMA
- Olivier Aubin-Mercier 21-5-0 · Lightweight · PFL
- Olivier Murad 7-2-0 · Featherweight · CZ
- Ollie Schmid 4-3-0 · Featherweight · UFC
- Oluwale Bamgbose 6-4-0 · Middleweight · UFC
- Omar Morales 11-4-0 · Lightweight · UFC
- Omari Akhmedov 24-8-1 · Light Heavyweight · PFL
- Omran Chaaban 10-1-0 · Welterweight · PFL
- Onassis Parungao 2-1-0 · Light Heavyweight · IAFC
- Ondřej Raška 12-10-0 · Middleweight · OKMMA
- Orion Cosce 8-2-0 · Middleweight · UFC
- Orlando Welt 1-5-0 · Welterweight
- Oscar Cota 11-3-0 · Heavyweight · DWCS
- Oskar Piechota 11-3-1 · Middleweight · UFC
- Ottman Azaitar 13-3-0 · Lightweight · UFC
- Oumar Sy 12-2-0 · Light Heavyweight · UFC
- Ousmane Thomas Diagne 6-8-1 · Lightweight · URCC
- Ovince St. Preux 27-18-0 · Light Heavyweight · UFC
- Ozzy Diaz 10-4-0 · Middleweight · UFC