Vitamin String Quartet (VSQ) is an American musical group from Los Angeles known for its series of tribute albums to rock and pop acts.

VSQ is a series of string quartet projects developed and produced by CMH Records, an independent record company based in Los Angeles. The CMH team works with an evolving cast of arrangers, producers, string players, and other creatives on each project. Their albums are released through Vitamin Records and are primarily performed by a string quartet, although other instruments have been used. "Vitamin String Quartet is about applying rock n' roll attitude to classical technique," said Tom Tally, a violist and arranger who has performed on and produced over 50 Vitamin String Quartet albums.

Their albums feature various genres, including pop and rock, metal, emo, punk, techno, country, and hip-hop, and a wide variety of groups, such as The Beach Boys, Gorillaz, Oasis, 311, Depeche Mode, Simple Plan, Queen, Led Zeppelin, The Offspring, Rush, Michael Jackson, The Beatles, Senses Fail, Black Sabbath, Iron Maiden, Bruce Springsteen, Crossfade, Jimi Hendrix, The Smashing Pumpkins, Radiohead, Modest Mouse, System of a Down, The Killers, Red Hot Chili Peppers, Coldplay, Linkin Park, Muse, Thirty Seconds to Mars, Slayer, Kanye West, Adele, Lady Gaga, and Lana Del Rey, among others. Their discography includes over 400 albums.

The group began in 1999 "as an experiment in transforming rock and pop songs with classical instruments." It later expanded to include a variety of popular music.

From 2012 until 2014, their music was played 24 hours a day on the FM broadcast station WWHK in Concord, New Hampshire.