ALS

ALS may refer to:
* Acetolactate synthase, an enzyme involved in amino acid biosynthesis
* Albany Law School, a private law school in Albany, New York, United States
* Alexander Language Schools International
* Als, a Danish island in the Baltic Sea
* Amyotrophic lateral sclerosis, also known as Lou Gehrig's disease
* Advanced Life Support, a protocol for cardiopulmonary resuscitation
* Advanced Light Source, a synchrotron radiation source at Lawrence Berkeley National Laboratory in California
* Anti-Lag System, an engine control program used on race cars to eliminate turbo lag
* Anterolateral system, a nerve pathway mainly signaling pain and temperature
* Approach lighting system, a lighting system installed on the approach end of an airport runway
* Audio Lossless Coding, part of the MPEG-4 standard for audio/video compression
* Airman Leadership School, the first-level professional military education program for United States Air Force enlisted members
* Alliance for the Liberation of Somalia
* ALS, San Luis Valley Regional Airport's IATA airport code
* Autographed Letter Signed
* als, the ISO 639-3 code for Tosk Albanian
* Automated library system or integrated library system
* Automatic Laser Shutdown
* Alternate line service, a GSM feature for supporting two different phone numbers on the same mobile device.
* Singapore Area Licensing Scheme