The Fred Frith Guitar Quartet was an American-based contemporary classical and experimental music guitar quartet comprising Fred Frith, René Lussier, Nick Didkovsky and Mark Stewart.

"[2] The quartet comprised four "avant-garde" guitarists and composers: Englishman Fred Frith from Henry Cow, French Canadian René Lussier from Conventum, and United States musicians Nick Didkovsky from Doctor Nerve and Mark Stewart from Bang on a Can.

Frith had been collaborating with Lussier on various projects since the early 1980s, had performed regularly with Stewart, and had produced Doctor Nerve's album, Armed Observation (1987).

[5] Their second album, Upbeat was drawn from concerts the quartet had performed in Austria, Germany, Switzerland, France and Spain in November 1997.

It contained composed material from each of the group members, plus improvised pieces, and was released on Ambiances Magnétiques in 1999.