MSO is an abbreviation that may stand for:

Orchestras

• Madison Symphony Orchestra, of Madison, Wisconsin, USA
• Melbourne Symphony Orchestra, of Melbourne, Victoria, Australia
• Metropolitan Symphony Orchestra, of Minneapolis, Minnesota, USA
• Milwaukee Symphony Orchestra, of Milwaukee, Wisconsin, USA
• Montreal Symphony Orchestra, of Montreal, Quebec, Canada

Companies and organizations

• Mara Students' Organizations, a student umbrella of Mara people in Northeastern state of Mizoram and their presence around the world.
• Martha Stewart Living Omnimedia, a merchandising company founded by Martha Stewart
• Management services organization, an organization providing admin services for individual physicians
• Michigan Southern Railroad, a wholly-owned subsidiary of Pioneer Railcorp
• Mind Sports Organization, a vehicle for promoting mental-skill games
• Multi system operator, an operator of multiple cable television systems

Other uses

• Maritime Security Operations, a method of policing various illegal activities at sea
• Manufacturer Statement of Origin, a document of ownership, usually related to a motor vehicle
• Medical Support Officer, a rank within the British Army Royal Army Medical Corps
• Microsoft Office, a set of interrelated desktop applications, servers and services
• Missoula International Airport, public airport located in Montana, USA (IATA code: MSO)
• Monadic Second-order logic, in mathematics
• Mountain Skies Observatory, an astronomical observatory Wyoming, USA
• Murashige and Skoog medium, a plant growth medium used in laboratories for cellular cultivation
• Minesweeper (ship), a class of naval warship designed to clear naval mines
• Moston railway station, a railway station in Greater Manchester, England (National Rail code: MSO)
• Mixed Service Organisation, Displaced Persons employed by the British Army on the Rhine in various positions up until the end of the Cold War

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