| Rated Maximum Sinusoidal | Academic & Science |
| Rossijskoe Mineralogičeskoe Obŝestvo | Academic & Science |
| Российское Минералогическое Общество | Academic & Science |
| Russian Mineralogical Society | Academic & Science |
| Royal Meteorological Society | Academic & Science |
| Royal Microscopical Society | Academic & Science |
| Reloadable Motor System | Academic & Science |
| Recipe Management Standard | Academic & Science |
| Real Modulated Signal | Academic & Science |
| Reims Management School | Academic & Science |
| Radnor Middle School | Academic & Science |
| Robert May’s School | Academic & Science |
| Richland Middle School | Academic & Science |
| Romulus Middle School | Academic & Science |
| Rambhakta Memorial School | Academic & Science |
| Receivables Management Service | Accounts and Finance |
| Receivables Management Solutions | Accounts and Finance |
| Ramstein | Airport Code |
| Rostral Migratory Stream | Animal Kingdom |
| named after the musicians: Ray Russell, Mo Foster & Simon Phillips | Arts |
| Ramanujan Mathematical Society | Associations & Organizations |
| Real Marketing Solutions | Business |
| Ramelius Resources, LTD. | Business |
| Risk Management System | Business |
| Risk Management Solutions | Business |
| Records Management System(s) | Business |
| Records Management strategy/ies | Business |
| Residential Mortgage Services | Business |
| Residential Management Services | Business |
| Risk Management Solution | Business |
| Retail Management System | Business |
| Roll Music Studios | Business |
| Records Management System | Business |
| Rouse Matrix Systems | Business |
| Rotana Media Services | Business |
| Recruitment Management System | Business |
| Resource Management Service | Business |
| Rental Management Software | Business |
| Rail Management Services | Business |
| Revenue Management Solutions | Business |
| Resource Management Suite | Business Management |
| Recovery Management Services | Business Management |
| Robot Management System | Business Management |
| Ramblewood Middle School | Community |
| Rockcliffe Middle School | Community |
| Rosemount Middle School | Community |
| Rotolo Middle School | Community |
| Riverside Middle School | Community |
| Ridgely Middle School | Community |
| Richmond Middle School | Community |
| Roosevelt Middle School | Community |
| Residential Media Systems | Community |
| Robertsville Middle School | Community |
| Ritenour Middle School | Community |
| Reading Motivation System | Community |
| Ratner, Miller, and Shafran Families Foundation | Community |
| Richard Matthew Stallman, activist | Community |
| Rockford Middle School | Community |
| Riverton Middle School | Community |
| River Management Society | Community |
| Rivera Middle School | Community |
| Realtime Music Solutions | Community |
| Root Mean Square | Computer and Networking |
| Relocated Module Segment | Computer Assembly Language |
| Remote Technical Support | Computing |
| Rack Mount Space | Computing |
| Resource Management Scheduling | Computing |
| Resource Management System | Computing |
| Remote Management Solution | Computing |
| Random Music Sensor | Computing |
| Remote Management System | Computing |
| Record Management Services | Computing |
| Reliant Monitor Software | Computing |
| Rack Mount Systems | Computing |
| Rack Mount Server | Computing |
| Remote Management Server | Computing |
| Reliable Multicast Service | Computing |
| Retail Merchandise System | Computing |
| Remote Monitoring Services | Computing |
| Recipe Management Systems | Computing |
| Rich Media Session | Computing |
| Release Management System | Computing |
| Record Management System | Computing |
| Random Map Script | Computing |
| Random Mapping Series | Computing |
| Rights Management Services | Computing |
| Rate-Monotonic Scheduling | Computing |
| Reformed Mission Services | General |
| Royal Mail Steamer | General |
| Root Mean Squared | General |
| Royal Marine Service | General |
| Regression Modeling Strategies | General |
| Royal Marine Steamer | General |
| Remote Manipulator System | General |
| Reflex Mini Sight | General |
| Raw Material Surcharge | General |
| Rageing Mammoth Society | General |
| Real Maximum Something | General |
| Ron Montris Stumped | General |
| Richard M Stallman | General |
| Royal Mail Steamship | General |
| Really Massive Ship | General |
| Retail Merchandising Services | General |
| Rotronic Monitoring System | General |
| Rotary and Mission Systems | General |
| Related Moment Series | General |
| Rose Marie Swift | General |
| Rotating Machinery Services | General |
| Remote Starter | General |
| Road Management System | General |
| Ramp Metering System | General |
| Renault Megane Scenic | General |
| Rocky Mountain Sprints | General |
| Renault Multi Sense | General |
| Rear Sensing Misacceleration Mitigation System | General |
| Red Means Stop | General |
| Radar Sensing Misacceleration Mitigation System | General |
| Reference Member State | Governmental |
| Regulatory Management System | Governmental |
| Review Management Staff | Governmental |
| Roads and Maritime Services (NSW, Australia) (replaced RTA 2011?) | Governmental |
| Risk Mitigation Strategy | Governmental |
| Resolution Management System | Governmental |
| Remote Monitoring System | Governmental |
| Railway Mail Service | Governmental |
| Roads & Maritime Services | Governmental |
| Regroupement des Militants Syndicaux | Governmental |
| RAMSHAI | Indian Railway Station |
| Richard Matthew Stallman | Information Technology |
| Ride me sideways | Internet Slang |
| RhabdoMyoSarcoma | Medical |
| Respiratory Monitoring System | Medical |
| Royal Medical Society | Medical |
| Resource Monitoring Subsystem | Military and Defence |
| Requirements Management System | Military and Defence |
| Remote Management Service | Networking |
| Received Message Store | Networking |
| Rate My Signal | Radio Science |
| Rooms | Real Estate |
| Ramstein Airbase, Kaiserslautern, Germany | Regional |
| Republik Maluku Selatan | Regional |
| Resource Monitoring System | Softwares |
| Risk Management and Safety | Space Science |
| Reliability, Maintainability, and Safety | Space Science |
| Radian Means Per Second | Space Science |
| Random Motion Simulator | Space Science |
| Redundancy Management System | Space Science |
| Remote Manipulator System (subsystem) | Space Science |
| Race Marque Systems | Sports |
| Reconfigurable Manufacturing System | Technology |
