OSI was an American progressive rock band, originally formed by Fates Warning guitarist Jim Matheos in 2002. Chroma Key keyboardist and vocalist Kevin Moore is the only other full-time member of the band. The collaboration may be considered a studio project, as its members and contributors write and track most of their material independently, sharing and developing tracks long-distance, only coming together at the end of the process for mixing and additional tracking. The band's name is a reference to the Office of Strategic Influence, a short-lived American government agency formed in 2001 to support the War on Terror through propaganda. The band has featured a number of guest musicians on its albums, including Sean Malone, Steven Wilson, Mikael Akerfeldt, Joey Vera and Gavin Harrison.

Jim Matheos is an American guitarist and the primary songwriter for the progressive metal band Fates Warning, in which he has been the only consistent member since the group's beginning. Matheos also plays in OSI alongside Kevin Moore, as well as making other appearances with many different bands and artists.