| Acronym | Definition |
|---|
| MSB | Most Significant Bit |
| MSB | McDonough School of Business (Georgetown University) |
| MSB | Matanuska-Susitna Borough (Palmer, OK) |
| MSB | Most Significant Byte (multiple byte sequences) |
| MSB | Michael Stanley Band |
| MSB | Money Services Business (non-bank financial institution) |
| MSB | Middle School Boys (various locations) |
| MSB | Michigan State (University) Broadcasting |
| MSB | Midsize Business |
| MSB | Media Stream Broadcast |
| MSB | Most Significant Byte |
| MSB | Marshall & Swift/Boeckh (insurance; various locations) |
| MSB | Magic School Bus |
| MSB | McCluer South Berkeley (school; St. Louis, MO) |
| MSB | Monthly Statistical Bulletin (various locations) |
| MSB | Marshall School of Business (University of Southern California) |
| MSB | Municipal Services Building |
| MSB | Molecular and Structural Biology (various schools) |
| MSB | Mauritius Standards Bureau |
| MSB | Mangala Shri Bhuti (Buddhist organization; Colorado; est. 1989) |
| MSB | Medical Services Branch |
| MSB | Merage School of Business (University of California, Irvine) |
| MSB | Music Soundtrack Book (Middlesex University; London, UK) |
| MSB | Minimum Sideband (modulation) |
| MSB | Military Science Building (various locations) |
| MSB | Malawi Savings Bank |
| MSB | Medical Sciences Bulletin |
| MSB | Medical School Building (University of Texas Health Science Center - Houston) |
| MSB | The Robert Emmett McDonough School of Business (Georgetown University) |
| MSB | Mortality Statistics Branch (US CDC) |
| MSB | Membership Services Board (various organizations) |
| MSB | Minesweeping Boat |
| MSB | Modular Sleeping Bag |
| MSB | Microsoft Security Bulletin |
| MSB | Michelmersh Silver Band (UK) |
| MSB | Maryland State Boychoir |
| MSB | Michigan School for the Blind |
| MSB | Melbourne Staff Band (Melbourne, Australia) |
| MSB | Marxistischer Studentenbund (Marxist Students Federation) |
| MSB | Magic Store Builder (various locations) |
| MSB | Milli Savunma Bakanligi |
| MSB | Marine Safety Branch (Canada) |
| MSB | Magnetic Susceptibility Balance |
| MSB | Mississippi School for the Deaf |
| MSB | Main Switch Board |
| MSB | Motorized Seatbelt (vehicles) |
| MSB | Monetary Stabilization Bond |
| MSB | Mid Size Bentley |
| MSB | Massive Sperm Buildup |
| MSB | Managing Student Behaviour (Australia) |
| MSB | Multiple-Synapse Boutons |
| MSB | Missile Support Base |
| MSB | Mobile Sea Base |
| MSB | Memory Storage Buffer |
| MSB | Middletown Symphonic Band (Middletown, CT) |
| MSB | Manufacturer Specified Blocks |
| MSB | Minimum Security Baseline (IT security) |
| MSB | Michigan Association of School Boards |
| MSB | Molecular Sieve Bed |
| MSB | Minnesota State Band (Saint Paul, MN) |
| MSB | Mechanism Selection Box |
| MSB | Modern Strategic Bomb |
| MSB | Maintenance Standards Book |
| MSB | Mechanized Summary Billing |
| MSB | Main Street Bath, Inc. (Maine) |
| MSB | Main Support Base/Battalion |
| MSB | Mixing/Shearing/Blending |
| MSB | Minimal Segmental Buckling (eye surgery) |
| MSB | Message Storage Buffer |
| MSB | Member of the Society of Biology (UK) |
| MSB | Masters of Science in Bioethics (various locations) |
| MSB | Multiple Switch Board |