MSA may refer to:

Organisations and businesses

• Malaysia-Singapore Airlines, now Singapore Airlines and Malaysia Airlines separately
• Masonic Service Association, a Freemason resource that publishes the monthly Short Talk Bulletin since 1923
• Management Science Associates, Inc., Innovators of the collection, processing, analysis, and delivery of mission-critical information
• Medical Supplies Agency, part of the United Kingdom's Armed Forces procurement system
• Mine Safety Appliances, a manufacturer of industrial safety clothing and equipment
• Mineralogical Society of America, a scientific organization founded for the advancement of mineralogy
• Motor Sports Association, the governing body for motorsport in the United Kingdom
• Motorsport South Africa, a member of the FIA
• Mycological Society of America, a scientific society promoting the study of fungi
• Matsqui-Sumas-Abbotsford Hospital (or other regional organization) in Abbotsford, British Columbia

Education

Degree

• Master of Accountancy (Master of Science in Accountancy), a post-graduate professional accounting degree
• Master of Science in Administration, a post-graduate degree providing preparation for a variety of administrative positions

School

• Manatee School for the Arts
• Maryland School of the Arts, a fictional dance school in Step Up (film) and Step Up 2 the Streets
• Manchester School of Architecture, an architecture school in Greater Manchester, England
• Math and Science Academy, a school in Minnesota
• Middle States Association of Colleges and Schools, a non-profit association dedicated to educational excellence and improvement through peer evaluation and accreditation
• Mississippi School of the Arts, a residential high school for the arts in Brookhaven, MS
• Missouri Scholars Academy, a three-week residential summer program held on the University of Missouri's Columbia campus
• Modern Sciences and Arts University, a university providing British education in October City, Egypt
• Monash Student Association, the student government association of the Monash University, Melbourne, Australia
• Muslim Students' Association, a group dedicated to Islamic societies on college campuses in Canada and the United States

Science and technology

• Mannitol Salt Agar, an agar useful in microbiology
• Measurement Systems Analysis, the analysis of the entire process of obtaining measurements to ensure the integrity of data and to understand the implications of measurement error for decisions made about a product or process
• Middle Stone Age, a period of African Prehistory between Early Stone Age and Late Stone Age
• Multiple sequence alignment, an alignment of three or more biological sequences
• Multiple system atrophy, a degenerative neurological disorder
• Sulfonic acid (Methanesulfonic acid), an organic sulfonic acid

Transportation

• MSA Garratt, a steam engine class of the Western Australian Government Railways
• Motorway service areas (rest area), a public facility at which drivers and passengers can rest before commencing their journey
• Muskrat Dam Airport, the IATA code for the airport at Muskrat Dam, Ontario, Canada

Other

• Mail submission agent, an intermediary computer program or software agent which is used when sending email
• Mapping Services Agreement, a licensing contract between local authorities in the United Kingdom and suppliers of geographic data
• Market Square Arena, an indoor arena in Indianapolis, Indiana built in 1974 and demolished in 2001
• Tobacco Master Settlement Agreement (Master Settlement Agreement), an agreement reached between U.S. States and major tobacco companies
• Medical savings account, an account where tax-deferred deposits can be made for medical expenses
• Metropolitan Statistical Area, a geographical area associated with a U.S. urban area, as determined by the Census Bureau based on population and interaction.
• Literary Arabic (Modern Standard Arabic), the variety of Arabic used in most written media and some television talk shows in the Arabic-speaking world
• Mutual Security Agency which managed the Marshall Plan aid in Europe