| Acronym | Definition |
|---|
| MSI | Medium-Scale Integration (digital/electrical engineering) |
| MSI | Micro-Star International |
| MSI | Microsoft Installer (file extension) |
| MSI | Management Systems International (Washington, DC) |
| MSI | Mindless Self Indulgence (band) |
| MSI | Marketing Science Institute |
| MSI | Microsatellite Instability |
| MSI | Marie Stopes International (London, UK) |
| MSI | Management Services Inc |
| MSI | Magnetic Source Imaging |
| MSI | Message Signaled Interrupt (PCI) |
| MSI | Maritime Safety Information |
| MSI | Micro Systems, Inc. |
| MSI | Master of Science in Information |
| MSI | Media Sports Investments (London, UK) |
| MSI | Microstrategy Inc. |
| MSI | Medicare Supplemental Insurance |
| MSI | Mindless Self Indulgance (band) |
| MSI | Member of the Securities Institute |
| MSI | Management Simulations, Inc. |
| MSI | Metapath Software International |
| MSI | Mass Storage Interface |
| MSI | Multi Sensor Integration |
| MSI | Marine Systems Inc. (Kirby Corporation) |
| MSI | Marine Systems International (New Brunswick, Canada) |
| MSI | Mental Sciences Institute (University of Texas Health Science Center at Houston) |
| MSI | Management Science Institute |
| MSI | Medium Scale Industries |
| MSI | Thousand Square Inches (area unit) |
| MSI | Maintenance Significant Item |
| MSI | Minesweeper, Inshore |
| MSI | Modified Surf Index |
| MSI | Multi-Simulator Interface |
| MSI | Missão para a Sociedade da Informação (Portugal) |
| MSI | More Stupid Initials (band) |
| MSI | Manufacturer Specific Information |
| MSI | Mobilized Systems Inc. |
| MSI | Multi-Source, Inc. |
| MSI | Military Science I (first-year ROTC cadet) |
| MSI | Motor Sports International |
| MSI | Marketing, Strategy and Innovation (The Coca-Cola Company) |
| MSI | Morpho-Semantic Indexing |
| MSI | Mission Store Interface |
| MSI | Military Skills Instructor |
| MSI | Maximum Symbol Inversion |
| MSI | Maintenance Staff Instruction |
| MSI | Member Satisfaction Index (various organizations) |
| MSI | Major Service Interruption |
| MSI | Market Statistics, Inc. |
| MSI | Multisystem Integration |
| MSI | Maryland Sheriffs' Institute |
| MSI | Military Standard Item |
| MSI | Man-System Interface |
| MSI | Mustang Supply, Inc. |
| MSI | Maintenance Standard Instructions |
| MSI | Main Synthetic Intelligence (gaming) |
| MSI | Microprocessor Serial Interface |
| MSI | Makiling School, Inc (Laguna, Philippines) |
| MSI | Master of Strategic Intelligence (degree) |
| MSI | MoreStudios, Inc. (marketing and design firm) |
| MSI | Mouse Subinoculation |
| MSI | Merit Salary Increment |
| MSI | Mass Sensors, Inc (St. Louis, MO) |
| MSI | Maximum Security Installation |
| MSI | Multispectral Scan Imaging |
| MSI | Missile System Interface |
| MSI | McDermott Shipbuilding, Inc. |
| MSI | Military Service Indicator |
| MSI | Management Support Item |
| MSI | Multisensor/Multisource Interaction |
| MSI | Multisignal Interconnect |
| MSI | Missionary Sisters of Immaculate |
| MSI | Material Strength Index |
| MSI | Market Strategy Implementation |
| MSI | Munitions Storage Igloo |
| MSI | Manpower Standard Implementation (US DoD) |
| MSI | Medical Services International (various organizations) |
| MSI | Mitsui Sumitomo Insurance (various insurances) |
| MSI | Multi-Stakeholder Initiative |
| MSI | Multispectral Imager |
| MSI | Musculoskeletal Injury |
| MSI | Mustang Software, Inc. |
| MSI | Movimento Sociale Italiano (Italian political party) |
| MSI | Measurement Systems Inc. (Ultra Electronics; Wallingford, CT) |
| MSI | Management Software, Inc. (various locations) |
| MSI | Manufacturing Systems, Inc. (various locations) |
| MSI | Mutual Service Casualty Insurance Co. |
| MSI | Multi-Systems, Inc. |
| MSI | Medicine Shoppe International, Inc. (Cardinal Health; various locations) |
| MSI | Millennium Software, Inc. (various locations) |
| MSI | Magna Services Inc. |
| MSI | Messe Stuttgart International (Germany) |
| MSI | Maruti Suzuki India (car manufacturer) |
| MSI | Medical Supply, Inc. (various locations) |
| MSI | multi-spectral imagery (US DoD) |
| MSI | Microbial Sciences Initiative (Harvard University; Boston, MA) |
| MSI | Molecular Simulations, Inc. (various locations) |
| MSI | Multi-Source Integration (electronic signatures) |
| MSI | Mechanical Services, Inc. (various locations) |
| MSI | Manufacturers Sales Incentive (automobile sales) |
| MSI | Museum of Science and Industry (Chicago, IL) |