FSB may refer to:
Organizations
- Federal Security Service of the Russian Federation (Russian: Федера́льная слу́жба безопа́сности Росси́йской Федера́ции (ФСБ), tr. Federálʹnaja Slúžba Bezopásnosti Rossíjskoj Federácii (FSB), the principal security agency of the Russian Federation and main successor to the defunct Committee for State Security (KGB) of the Soviet Union
Banking and finance
- Federal savings bank, a class of bank in the United States
- Federation of Small Businesses, a British lobbying group
- Financial Services Board (South Africa), a financial regulatory authority
- Financial Stability Board, an international group of financial authorities
- First Somali Bank, a bank headquartered in Mogadishu, Somalia
- Swedbank, formerly FöreningsSparbanken, a retail banking group
Computing
- Fast syndrome-based hash, cryptographic hash functions
- Front-side bus, a computer communication interface
Schools
- Farmer School of Business, at Miami University in the U.S. state of Ohio
- Friends School of Baltimore, a Quaker institution in Baltimore
- Fuqua School of Business, at Duke University in the U.S. state of North Carolina
Other
- FSB (band), a Bulgarian band
- Bolivian Socialist Falange (Spanish: Falange Socialista Boliviana), a Bolivian political party
- Brinjal fruit and shoot borer (Leucinodes orbonalis), a moth species
- Fellow of the Society of Biology, U.K.
- Fire support base, a temporary military encampment
- Fishbourne railway station, in England
- Fortune Small Business, a defunct magazine
- Trade Union Social Citizens List (Danish: Faglig Social Borgerliste), a Danish political group