| Fighter | Record | Last Bout |
|---|---|---|
| Roan Carneiro | 21-11-0 | 2017-02-11 |
| Rob Broughton | 16-7-1 | 2011-11-05 |
| Rob Emerson | 18-12-0 (1 NC) | 2010-03-31 |
| Rob Kimmons | 25-9-0 | 2011-03-03 |
| Rob MacDonald | 5-4-0 | 2006-08-26 |
| Rob Wilkinson | 11-2-0 | 2018-02-10 |
| Rob Yundt | 9-5-0 | 2008-06-21 |
| Robbie Lawler | 30-16-0 (1 NC) | 2023-07-08 |
| Robert Drysdale | 7-0-0 (1 NC) | 2014-07-06 |
| Robert Lucarelli | 0-1-0 | 1994-03-11 |
| Robert McDaniel | 28-10-0 | 2014-03-15 |
| Robert Peralta | 18-8-0 (1 NC) | 2015-04-04 |
| Robert Sanchez | 8-2-0 | 2018-09-08 |
| Robert Whiteford | 14-4-0 | 2016-04-10 |
| Roberto Traven | 6-4-1 | 2001-11-02 |
| Rocky Lee | 3-2-0 | 2015-04-11 |
| Rodney Wallace | 26-15-1 | 2010-08-07 |
| Rodolfo Rubio Perez | 10-16-1 | 2014-11-08 |
| Rodrigo Damm | 13-9-0 | 2015-01-03 |
| Rodrigo Ruas | 4-5-1 (1 NC) | 2002-06-22 |
| Rodrigo de Lima | 8-3-1 | 2015-02-14 |
| Roger Bowling | 12-6-0 (1 NC) | 2013-12-14 |
| Roger Gracie | 8-2-0 | 2013-07-06 |
| Roger Hollett | 13-5-0 | 2013-05-18 |
| Roger Huerta | 23-9-1 (1 NC) | 2009-09-16 |
| Roger Narvaez | 8-3-0 | 2015-03-14 |
| Roger Zapata | 4-2-0 | 2015-09-26 |
| Rogerio Bontorin | 16-4-0 (2 NC) | 2022-01-15 |
| Rogerio Nogueira | 23-10-0 | 2020-07-25 |
| Roland Delorme | 9-5-0 (1 NC) | 2014-08-23 |
| Roland Payne | 0-1-0 | 1994-09-09 |
| Rolando Delgado | 11-6-1 | 2009-11-14 |
| Rolando Dy | 9-7-1 (1 NC) | 2018-06-23 |
| Roldan Sangcha'an | 4-2-0 | 2015-05-16 |
| Rolles Gracie | 8-4-0 | 2010-02-06 |
| Roman Bogatov | 10-1-0 | 2020-07-11 |
| Roman Mitichyan | 8-3-0 | 2008-04-02 |
| Roman Salazar | 10-6-0 (1 NC) | 2015-08-08 |
| Romie Aram | 7-1-0 | 2003-04-25 |
| Ron Faircloth | 33-20-0 (1 NC) | 2005-10-07 |
| Ron Stallings | 14-8-0 (1 NC) | 2015-09-05 |
| Ron Waterman | 16-6-2 | 2000-04-14 |
| Ron van Clief | 0-1-0 | 1994-12-16 |
| Ronald Jhun | 24-26-2 | 2004-08-21 |
| Ronda Rousey | 12-2-0 | 2016-12-30 |
| Ronnie Lawrence | 8-2-0 (1 NC) | 2023-06-17 |
| Ronny Markes | 17-5-0 | 2014-03-23 |
| Rony Jason | 14-7-0 (1 NC) | 2017-03-11 |
| Ronys Torres | 35-5-0 | 2010-03-31 |
| Roque Martinez | 15-8-2 | 2021-06-19 |