FRISK Software International (FSI), is an Icelandic software company that develops F-Prot antivirus and F-Prot AVES antivirus and antispam service. Its name is derived from the initial letters of the personal name and patronymic of Friðrik Skúlason, its founder. The company was founded in 1993.

F-Prot Antivirus is sold in both home and corporate packages, of which there are editions for Windows, Linux, and BSD. There was also a DOS version for home users, and there are corporate versions for Microsoft Exchange, Solaris, and certain IBM eServers. F-Prot has been produced since 1989. The DOS version was discontinued in 2007. The DOS version was and the Linux version is available to home users free of charge, with virus definition updates. Free 30-day trial versions for other platforms can be downloaded.

F-Prot AVES is for corporate users.

The company has also produced a genealogy program called Espólín and Púki, a spellchecker with additional features.

FRISK Software International should not be confused with F-Secure, another data security company, although they are historically related: at one time, F-Secure used FRISK's F-Prot anti-virus search engine for their anti-virus product.

* The genealogy program Espólín is named after Jón Espólín, a 18th century magistrate of Snæfellsnes.
* The name of the spellchecker "Púki" stands for "demon" in a similar sense as the BSD Daemon.