Free Speech Movement, at the University of California, Berkeley, in 1964

Federated States of Micronesia, an Oceanic island nation

Finite state machine, an abstract machine, in logic and computer science

Film Score Monthly, a record label and former magazine

Flying Spaghetti Monster, the deity of the satire religion Pastafarianism

Free Software Movement, a sociopolitical movement in computing

Fighting Spirit magazine, a professional wrestling periodical

Free Software Magazine, a computing periodical/website

FIFA Soccer Manager, a video game about football management

Fort Smith Regional Airport (IATA code: FSM) in Arkansas, United States

Frame, Set & Match, a film post-production studio in Sydney, Australia

Folded spectrum method, a Solver for Eigenvalue problems