| | RAID | | Redundant Arrays of Inexpensive Disks |
| | RAK | | Random Act of Kindness |
| | RAOFLMAO | | Rolling Around On the Floor Laughing My Arse Off! |
| | raotflmao | | rolling all over the floor laughing my ass of |
| | raotflmao | | Rolling around on the floor laughing my ass off |
| | RAS | | Remote Access Service |
| | RATM | | Rage Against the Machine |
| | RAV | | Recreational Active Vehicle |
| | RBAC | | role based access control |
| | RBAR | | Row By Agonizing Row |
| | rbay | | right back at ya |
| | rbay | | right back at you |
| | RBL | | Raltime Blackhole List |
| | RBS | | Really Big Screen |
| | RBY | | Red, Blue, Yellow |
| | RC | | Release Candidate |
| | RC | | remote control |
| | RC | | Roman Catholic |
| | RCCB | | Residual Current Circuit breaker |
| | RCCB | | Residual Current Circuit breakers |
| | RCG | | recent college graduate |
| | RCG | | Reverse Cow Girl |
| | RCMP | | Royal Canadian Mounted Police |
| | RDB | | Relational DataBase |
| | RDBMS | | Relational Data-Base Management System |
| | RDBMS | | Relational Database Management System |
| | RDF | | Resource Description Format |
| | RDF | | Resource Description Framework |
| | RDI | | Recommended Daily Intake |
| | rdo | | regular day off |
|