Amyotrophic lateral sclerosis, also known as Lou Gehrig's disease or Maladie de Charcot

Autographed Letter Signed

Automated library system or integrated library system

Als, a Danish island in the Baltic Sea

Anti-Lag System, an engine control program used on race cars to eliminate turbo lag

Advanced Life Support, a protocol for cardiopulmonary resuscitation

Approach lighting system, a lighting system installed on the approach end of an airport runway

Airman Leadership School, the first professional military education for United States Air Force enlisted members

Alliance for the Liberation of Somalia

Audio Lossless Coding, part of the MPEG-4 standard for audio/video compression

Advanced Light Source, a synchrotron radiation source at Lawrence Berkeley National Laboratory in California

ALS, San Luis Valley Regional Airport's IATA airport code

als, the ISO 639-3 code for Tosk Albanian

Alternate line service, a GSM feature for supporting two different phone numbers on the same mobile device.

Anterolateral system, a nerve pathway mainly signaling pain and temperature