| Acronym | Meaning |
| ROFL | Rolling On Floor Laughing |
| ROR | Raffing Out Roud ("Laughing Out Loud" In Scooby-doo Dialect) |
| ROTFL | Rolling On The Floor Laughing |
| ROTFLMAO | Rolling On The Floor Laughing My Ass Off |
| ROTFLMFAO | Rolling On The Floor Laughing My F*cking Ass Off |
| ROTFLOL | Rolling On The Floor Laughing Out Loud |
| ROTGL | Rolling On The Ground Laughing |
| ROTGLMAO | Rolling On The Ground Laughing My Ass Off |
| ROTM | Right On The Money |
| RPG | Role Playing Games |
| RRQ | Return Receipt Request |
| RRR | HaR HaR HaR (instead Of LOL) |
| RSN | Real Soon Now |
| RSVP | R?pondez S'il Vous Pla?t (French For, Reply If You Please) |
| RT | Real Time |
| RTBM | Read The Bloody Manual |
| RTBS | Reason To Be Single |
| RTFAQ | Read The FAQ |
| RTFF | Read The F*cking FAQ |
| RTFI | Read The F*cking Instructions |
| RTFM | Read The F*cking Manual |
| RTFQ | Read The F*cking Question |
| RTH | Release The Hounds |
| RTI | Read The Instructions |
| RTK | Return To Keyboard |
| RTM | Read The Manual |
| RTSM | Read The Silly Manual |
| RTTSD | Right Thing To Say Dude |
| RTWFQ | Read The Whole F*cking Question |
| RU | Are You? |
| RU/18 | Are You Over 18? |
| RUFKM | Are You F*cking Kidding Me? |
| RUH | Are You Horny? |
| RUMCYMHMD | Are You On Medication Cause You Must Have Missed A Dose |
| RUMORF | Are You Male OR Female? |
| RUNTS | Are You Nuts? |
| RUOK | Are You OK? |
| RUS | Are You Serious? |
| RUSOS | Are You SOS (in Trouble)? |
| RUT | Are You There? |
| RUUP4IT | Are You Up For It? |
| RX | Regards |
| RYFM | Read Your Friendly Manual |
| RYO | Roll Your Own |
| RYS | Read Your Screen |
| S | Smile |
| S2R | Send To Receive |
| S2U | Same To You |
| S4L | Spam For Life |
| SADAD | Suck A Dick And Die |