RMS

• Ramstein Air Base, in Germany (IATA code RMS)
• {{lang|id|Republik Maluku Selatan|italic=no}} (Republic of the South Moluccas), a self-proclaimed republic in the Maluku Islands, founded in 1950

• Ramanujan Mathematical Society, a learned society founded in 1985 in India
• Royal Medical Society, a learned society founded in 1737 at the University of Edinburgh Medical School
• Royal Meteorological Society, a learned society founded in 1850 in Aylesbury in Buckinghamshire
• Royal Microscopical Society, a learned society founded in 1839 in London, now headquartered in Oxford
• Russian Mineralogical Society, a learned society founded in 1817 in Saint Petersburg
• Russian Musical Society, a learned society founded in 1859 and disbanded in 1917

• Radnor Middle School, in Radnor, Pennsylvania
• Redwood Middle School (Saratoga, California)
• Rice Middle School, in Plano, Texas
• Richardson Middle School, in Chicago, Illinois
• Richland Middle School, in Richland Hills, Texas
• Riverwood Middle School, in Kingwood, Texas
• Robinson Middle School, in Plano, Texas
• Rocky Mountain semester, in Leadville, Colorado; now called High Mountain Institute Semester
• Romulus Middle School, in Romulus, Michigan
• Roosevelt Middle School (Oakland, California)
• Rosemount Middle School, in Rosemount, Minnesota
• Ridgely Middle School, in Lutherville, Maryland

• Rambhakta Memorial School in Banepa, Kavre, Nepal
• Reims Management School, in Reims, France
• Robert May's School, in Hampshire, England
• The Royal Masonic School for Girls, in Hertfordshire, England
• Rutland Middle School, in British Columbia, Canada

• Hermès (Euronext Paris: RMS), a French luxury fashion house
• Railway Mail Service, a former US mail transportation service
• Raytheon Missile Systems, a former company which manufactured missiles
• Regroupement des militants syndicaux ("Trades-Union Militants Grouping"), a political organization in Quebec, Canada, in the 1970s
• Revenue Management Society, a British industry organisation
• Risk Management Solutions, a subsidiary of Moody's Corporation
• RMS, a prefix for Royal Mail Ships and aircraft, UK
• Roads and Maritime Services, a former agency of the New South Wales government, Australia
• Rotana Media Services, the advertising and marketing wing of Rotana Group
• Rotating Memory Systems, Inc., a defunct hard disk drive manufacturer
• Royal Society of Miniature Painters, Sculptors and Gravers, originally the Royal Miniatures Society, London

• Rhabdomyosarcoma, a cancer of connective tissues
• Rostral migratory stream, one path that neuronal stem cells travel along to reach the olfactory bulb
• Relapsing Multiple Sclerosis

• Rate-monotonic scheduling, a scheduling technique in operating systems
• Record Management Services, file-management processes in OpenVMS operating systems
• Record Management System, a persistent storage mechanism available to some Java ME configurations
• Rights Management Services, a component of MS Windows Server 2003

• Reconfigurable Manufacturing System, designed for rapid change in its structure
• Residual mean square, a measure of the difference between data and a model of that data
• Revenue Management System (or revenue management software), a software system for managing occupancy in hotels and suchlike
• RMS (noise reduction) ({{lang|de|Rauschminderungssystem}}), a Dolby-B-compatible compander in the former GDR in the 1980s
• Root mean square, a measure of the magnitude of a varying quantity
• Royal Microscopical Society thread, or society thread, a screw thread used for microscope objective lenses
• "Watt RMS", an erroneous term for "average power" used in audio measurements

• Resilient Multi-mission Space STaR Shot program, a satellite defence program being developed by Airbus at Lot Fourteen in Adelaide, Australia
• Richard Matthew Stallman, often referred to as "rms", a software freedom activist and computer programmer
• RMS (band), a British jazz/rock fusion band, formed in 1982
• Royal Mail Ship, the ship prefix used for seagoing vessels that carry mail under contract to the British Royal Mail

{{disambiguation}}