BSI

BSI may refer to:

Businesses and organizations

 * BSI Ltd, formerly Banca della Svizzera Italiana
 * BSI Group or British Standards Institution
 * The Baker Street Irregulars, a literary society devoted to Sherlock Holmes
 * Bank Saderat Iran
 * Bank Syariah Indonesia
 * Bible Society of India
 * Botanical Survey of India
 * British Society for Immunology
 * Federal Office for Information Security (German: Bundesamt für Sicherheit in der Informationstechnik)
 * Bureau of Special Investigation, Myanmar

Other uses

 * BSI coupling, a railway coupling or coupler
 * Back-illuminated sensor, also known as backside illumination (BSI) sensor, a type of digital image sensor
 * Bloodstream infections
 * Body substance isolation
 * Balesin Airport, IATA code BSI