BAS may stand for:
Most commonly:
- BASIC programming language (file extension)
Societies:
- Biblical Archaeology Society
- Birmingham Astronomy Society
- Britain–Australia Society
- Bulgarian Academy of Sciences
In computer science:
- Broadband Access Server (see Broadband Remote Access Server)
In business administration:
- Business Augmentation Services (BAS)
Other:
- Bachelor of Applied Science
- Bachelor of Arts and Science
- Banc of America Securities
- Bay St. Louis (Amtrak station) (Amtrak station code BAS)
- Befreiungsausschuss Südtirol (South Tyrolean Liberation Committee)
- Behavioural Activation System
- Bergen School of Architecture (written Bergen Arkitekt Skole in Norwegian)
- Belt alternator starter hybrid vehicle system from General Motors
- Book of Alternative Services of the Anglican Church of Canada
- Brake assist system in an automobile
- British Art Show
- British Antarctic Survey
- Broadcast auxiliary service
- Building automation system
- Bulletin of Atomic Scientists
- Business Activity Statement, an Australian Taxation Office form
- Buttocks Augmentation Surgery
- Breast Augmentation Surgery
- Battalion Aid Station
- Basic Allowance for Subsistence
- BAS is the IATA airport code for Balalae, Solomon Islands.
- BAS is the SIL code and ISO 639 alpha-3, for the Bassa language of Liberia.
- Bank of America Stadium, a stadium in Charlotte, North Carolina and the home of the Carolina Panthers