| Abbreviation | Definition |
|---|---|
| R&B | Rocky Bullwinkle |
| R2 | King Richard II |
| RA | Richard Attenborough |
| RA | Roger Alden |
| RA | Roone Arledge |
| RA | Ruth Armstrong |
| RAC | Richard A. Clark, security expert and author |
| RaMBaM | Rabbi Moses Ben Maimmon (Maimonides) |
| RAW | Richard A. Watson, college professor |
| RB | Red Baron (Rittmeister Baron von Richtofen) |
| RB | Rob Berridge |
| RBH | Rutherford B. Hayes |
| RBO | Ryan Brennen O'Connor, musician |
| RC | Roger Curry |
| RC | Russ Collins |
| RCB | Robert C. Byrd |
| RDDP | Ruben Daniel Duarte Pereira |
| RDF | Raymond D. Findlay |
| RDJ | Robert Downey, Jr. |
| RDO | Ron D. Offutt, CEO of the R.D. Offutt Company |