FSI may refer to:
Economics Financial services industry Financial Secrecy Index, a ranking of secrecy jurisdictions Financial Stability Institute, a body of the Bank for International Settlements
Government and politics Federation of Italian Socialists (Italian: ), a defunct political party of Italy Foreign Service Institute, of the United States government Foreign Service Institute, India, an agency of the Indian government Forest Survey of India Fragile States Index, a country ranking method Internal Security Forces (French: ), the national security force of Lebanon
Technology First strong isolate, a Unicode character used to support Bidirectional text Flame spread index, a material's propensity to burn Fluid-structure interaction, in fluid dynamics Frequency scanning interferometry, a technique for measuring the distance between two points FRISK Software International, an Icelandic antivirus software developer FRU Support Interface, a simple bus for low-level access to IBM Power-based hardware FSI International, an American equipment manufacturer Fuel stratified injection Full spectral imaging, in spectroscopy
Other uses Fédération Ivoirienne du Scoutisme, the Ivorian Scouting Federation Ferrovie dello Stato Italiane, the Italian state-owned railway company FlightSafety International, an American aviation training provider Floor space index Florida Space Institute, of the State University System of Florida FontShop International, a German type foundry Fox Sports International Freeman Spogli Institute for International Studies, at Stanford University Free Sons of Israel, a fraternal organization IATA code for Henry Post Army Airfield, in Fort Sill, Oklahoma, United States Italian Chess Federation (Italian: ) Free-standing insert, a type of advertising: See