Places

• Als (island), Denmark

Aviation

• Airman Leadership School, a U.S. Air Force program

• ALS – Aircraft Leasing Services, a Kenyan airline

• Approach lighting system, an airport runway lighting system

• San Luis Valley Regional Airport, IATA code ALS

Medicine

• Advanced life support, a level of medical training

• Anterolateral system, part of the nervous system

• Antibodies from lymphocyte secretions, an immunological assay

Science and technology

• Acetolactate synthase, an enzyme

• Advanced Light Source, a synchrotron radiation facility

• ALSN, Automatic Train Signalling (автоматична локомотивна сигналізація), a train protection system

• Alternate line service, a mobile phone feature

• Aluminized Steel, as used in engineering drawings

• Ammonium lauryl sulfate, a household chemical

• Antilag system, a system used on turbocharged engines

• Audio Lossless Coding, an audio codec

• LS TTL, Advanced Low-power Schottky

• Photodetector, ambient light sensor

• Alternating least squares - matrix factorization method

Organizations

• Als, a nickname used for the Montreal Alouettes of the Canadian Football League

• ALS Association, an American nonprofit organization

• Arrowhead Library System (Wisconsin)

• Australian Linguistic Society

Other uses

• als, ISO 639-3 code for the Tosk Albanian language

• Alternative Learning System (Philippines), a modular non-formal education program

• Associate of the Linnean Society of London

• Autographed Letter Signed, a term related to auctions of autographs

• Singapore Area Licensing Scheme