BSB is a three-letter abbreviation that may refer to:
- Back-side bus, data bus in a computer
- Backstreet Boys, American vocal group
- Bandar Seri Begawan, Brunei
- Bank Services Billing Standard, international standard related to the structure of electronic bills sent by banks to their corporate customers
- Bank State Branch, six digit numerical code used within Australia to identify branches of financial institutions
- Bar Standards Board, professional regulator for barristers in England and Wales
- Bayerische Staatsbibliothek, Bavarian State Library
- Bournemouth School, Dorset, England
- Brigade Speciale Beveiligingsopdrachten, Dutch special forces
- British Satellite Broadcasting, former UK satellite television broadcaster
- British School of Brussels
- British Superbike Championship, motorcycle racing championship
- Broad Sustainable Buildings, building technique developed by a Chinese sustainable building group
- Presidente Juscelino Kubitschek International Airport, BrasÃlia, Federal District, Brazil
- The station code of Varanasi Junction, Varanasi, India
- BPO Standards Board, creators of the BPOSG