| Acronym | Definition |
|---|
| MARS | Military Affiliate Radio System (USA) |
| MARS | Monitoring, Analysis and Response System (Cisco) |
| MARS | Mortgage Assistance Relief Services (US FTC) |
| MARS | Multiple Active Result Sets |
| MARS | Multicast Address Resolution Server |
| MARS | Major Accident Reporting System |
| MARS | Multivariate Adaptive Regression Splines (statistical method) |
| Mars | Marsian (linguistics) |
| MARS | Mid-Atlantic Regional Spaceport (Wallops Island, Virginia) |
| MARS | Mars Arctic Research Station |
| MARS | Monterey Accelerated Research System (Monterey Bay) |
| MaRS | Medical and Related Sciences |
| MARS | Machine-Assisted Reference Section |
| MARS | Mobile Autonomous Robot Software |
| MARS | Mobile Augmented Reality Systems |
| MARS | Magenn Air Rotor System (wind turbine technology; Magenn Power Inc.) |
| MARS | Monitoring Agriculture with Remote Sensing |
| MARS | Molecular Adsorbents Recirculating System (medical device supporting liver function) |
| MARS | Mathematics Assessment Resource Service (UK) |
| MARS | Military Afloat Reach and Sustainability |
| MARS | Military Affiliate Radio Service (US DoD) |
| MARS | Marine Animal Rescue Society |
| MARS | Marine Accident Reporting Scheme |
| MARS | Maritime Mobile Access and Retrieval System |
| MARS | Military Amateur Radio System (common, but incorrect) |
| MARS | Mid-Atlantic Reptile Show |
| MARS | Merrick Advanced Remote Sensing |
| MARS | Middleware And Related Services |
| MARS | Metro Area Recumbent Society |
| MARS | Michigan Assistance and Referral Service |
| MARS | Military Armaments Research Syndicate (GI Joe: A Real American Hero toy) |
| MARS | Mobile Adjustable Ramp System |
| MARS | Management Analysis Reporting System |
| MARS | Mid-Atlantic Regional School of Professional Photography |
| MARS | Manatee Agricultural Reuse System (Florida, USA) |
| MARS | Maintainable Real-Time System |
| MARS | Medical Archival System |
| MARS | Mediation Arbitration Resolution Services |
| MARS | Multiuser Archival and Retrieval System |
| MARS | Mission to America's Remarkable Students (STS101) |
| MARS | Males Achieving Responsibility Successfully |
| MARS | Mongolian Amateur Radio Society |
| MARS | Mumbai Amateur Radio Society (Mumbai, India) |
| MARS | Mild Acute Respiratory Syndrome |
| MARS | Making All Recreation Safe |
| MARS | Mechanical Antireflection Switch |
| MARS | Milwaukee Area Radio Stations |
| MARS | Modeling with Automated Regression Tools |
| MARS | Multiple Artillery Rocket System |
| MARS | Mobile Aircrew Restraint System |
| MARS | Medication Administration Record Sheet |
| MARS | Mirror Advanced Reactor Study |
| MARS | Martial Arts Research Systems |
| MARS | Maritime Surface and Subsurface (Canadian Navy) |
| MARS | Mario Andretti Racing School |
| MARS | Maintenance And Repair System |
| MARS | Multiple-band Avionics Radio Suite (US Army) |
| MARS | Mobile Analytical Response System |
| MARS | Medical and Research Sciences |
| MARS | Metro Atlanta Racing Society |
| MARS | Memory-Aware Reference Stack |
| MARS | Multiple-Address Radio System |
| MARS | Membrane Anaerobic Reactor System |
| MARS | Manned Aerodynamic Reusable Spaceship |
| MARS | Monitoring At-Risk Students |
| MARS | Manned Astronomical Research Station |
| MARS | Mobile Atlantic Range Station |
| MARS | Multi-warfare Assessment and Research System |
| MARS | Multifunction Acquisition and Reporting System |
| MARS | Modular Aircraft Refueling System (Commercial and Military Refueling System) |
| MARS | Mutual Aid and Resource Sharing (Canada firefighting) |
| MARS | Multi-Arena Remote Simulator (Raytheon system to simulate message transmitter) |
| MARS | Materials At Risk Survey |
| MARS | Multi-Level Analysis and Reduction Suite |
| MARS | Multiple Application Reservoir Simulator |
| MARS | Multi-warfare Analysis and Research System |
| MARS | Microsoft Access Reports Scheduler (Microsoft Windows application) |
| MARS | Midair Retrieval System |
| MARS | Mobile Automatic Reporting System |
| MARS | Micromachined Angular Rate Sensor |
| MARS | Make A Radical Stand |
| MARS | Merrimack Access to Records System |
| MARS | Multi-parameter Arrhythmia Review Station |
| MARS | Manpower Access Report System (US Air Force) |
| MARS | Marketing Accounting Reporting System |
| MARS | Multi-warfare Assessment and Research Simulation |
| MARS | Marine Amphibious Reconnaissance System |
| MARS | Marketing Activity Reporting Systems (AMSEC) |
| MARS | Microcomputer-based Audit Retrieval System |
| MARS | Micro-Dynamics' Archiving and Retrieval System |
| MARS | Mission Maintenance & Reliability Simulation |
| MARS | Material Acquisition Resource |
| MARS | Multi Arena Remote System |
| MARS | Man-Hour Accounting & Reporting System |
| MARS | McGill Automated Registration Service |
| MARS | Mirror Advanced Reactor System (electron laser program at Lawrence Livermore National Laboratory) |
| MARS | Managed Asset Recovery Services (Crystal River, Florida) |
| MARS | Morgantown Auto Repair Service (Morgantown, WV) |
| MARS | Multicenter ACL (Anterior Cruciate Ligament) Revision Study (est. 2006) |
| MARS | Multiple Aircraft Ramp System (airports) |