FSB may refer to:
in business and economics:
- Financial Stability Board, an international group of financial authorities
- Swedbank, a retail banking group
- Fuqua School of Business, a business school
- Federal savings bank, a class of bank in the United States
- Federation of Small Businesses, a lobbying group of the United Kingdom
- Financial Services Board (South Africa), a financial regulatory authority
in politics:
- Federal Security Service (Russia), a domestic security service of Russia
- Bolivian Socialist Falange, a political party of Bolivia
- Trade Union Social Citizens List, a political group of Denmark
Other uses:
- FSB (band), a bulgarian music band
- Front-side bus, a computer subsystem
- Fast Syndrome Based Hash, a group of cryptographic functions
- Fire support base, a military encampment
- Friends School of Baltimore, a Quaker institution
- Brinjal fruit and shoot borer (Leucinodes orbonalis), a moth species
- FSB or FB, an acronym for fire support base or fire base used by the U.S. military during the Vietnam War