| MSO | A Multiple Satellite Organization 
| Others |
| MSO | Maajunga Spirit Orchestra
| Others |
| MSO | Madison Symphony Orchestra
| Others |
| MSO | Main Scientific Organizer
| Others |
| MSO | Managed Service Office
| Others |
| MSO | Managed Services Organization
| Others |
| MSO | Management Service Organization
| Others |
| MSO | Management Services Officer
| Others |
| MSO | Management Services Organization
| Others |
| MSO | Management Services Organizations
| Others |
| MSO | Managerial Share Ownership
| Others |
| MSO | Manufacturer's Statement of Origin
| Others |
| MSO | Manufacturers Statement of Origin
| Others |
| MSO | Map Support Office
| Others |
| MSO | Marine Safety Office
| Others |
| MSO | Maritime Security Operations
| Others |
| MSO | Marketing Services Organization
| Others |
| MSO | Maryland Symphony Orchestra
| Others |
| MSO | Massachusetts Society of Optometrists
| Others |
| MSO | McLaren Special
| Others |
| MSO | McLaren Special Operations
| Others |
| MSO | Mclaren's Special Operations
| Others |
| MSO | Medical Service Officer
| Others |
| MSO | Medical Service Organization
| Others |
| MSO | Medical Services Organization
| Others |
| MSO | Medical Stability Operations
| Others |
| MSO | Medical Support Officer
| Others |
| MSO | Memphis Symphony Orchestra
| Others |
| MSO | Mennonite Sports Organization
| Others |
| MSO | Metal Stamping Operations
| Others |
| MSO | Methylated Seed Oil
| Others |
| MSO | Michigan Southern Railroad
| Others |
| MSO | Michigan Southern Railroad Incorporated
| Others |
| MSO | Micro Service Objects
| Others |
| MSO | Microsoft Office
| Others |
| MSO | Midwestern Society of Orthodontists
| Others |
| MSO | Military Service Obligation
| Others |
| MSO | Military Source Operation
| Others |
| MSO | Military Strategic Objective
| Others |
| MSO | Military Support Operations
| Others |
| MSO | MILSATCOM (MILitary SATellite COMunications) Systems Organization
| Others |
| MSO | Milwaukee Symphony Orchestra
| Others |
| MSO | Mind Sport Olympiad
| Others |
| MSO | Mind Sports Olympiad
| Others |
| MSO | Mission Security Officer
| Others |
| MSO | Mississippi Symphony Orchestra
| Others |
| MSO | Missoula International Airport, Missoula, Montana USA
| Others |
| MSO | Mitch Schneider Organization
| Others |
| MSO | Mixed Signal Oscilloscope
| Others |
| MSO | Mobile Support Operative
| Others |
| MSO | Mobile Switching Office
| Others |
| MSO | Mobilization Staff Officer
| Others |
| MSO | Model for Spares Optimization
| Others |
| MSO | Modified Standard Orthography
| Others |
| MSO | Modified Stuxnet Object
| Others |
| MSO | Money Service Operator
| Others |
| MSO | Montreal Symphony Orchestra
| Others |
| MSO | Mortgage Sales and Originations
| Others |
| MSO | Most Serious Offense
| Others |
| MSO | Motor Sports Online
| Others |
| MSO | Mount Stromlo Observatory
| Others |
| MSO | Moving Swiftly On
| Others |
| MSO | Mozart Society Orchestra
| Others |
| MSO | Multi Shop Operations
| Others |
| MSO | Multi State Operator
| Others |
| MSO | Multi Sub Optimizer
| Others |
| MSO | Multi System Operator
| Others |
| MSO | Multi System Operators
| Others |
| MSO | Multiple Separate Offenses
| Others |
| MSO | Multiple Service Operator
| Others |
| MSO | Multiple System Operator
| Others |
| MSO | Multiple System Operators
| Others |
| MSO | Multiple System OperatorsB
| Others |
| MSO | Multiple Systems Operator
| Others |
| MSO | Muncie Symphony Orchestra
| Others |
| MSO | Muslim Student Organization
| Others |
| MSO | Mutual Service Office
| Others |
| MSO | Ocean Minesweeper (MineSweeper, Ocean)
| Others |