Allan Holdsworth (6 August 1946 – 15 April 2017) was a British jazz fusion and progressive rock guitarist, violinist and composer. He contributed to numerous bands, including Soft Machine, U.K., The Tony Williams Lifetime, Pierre Moerlen's Gong and Bruford, in addition to solo work.

Holdsworth was known for his esoteric and idiosyncratic usage of advanced music theory concepts, especially with respect to melody and harmony. His music incorporates a vast array of complex chord progressions, often using unusual chord shapes in an abstract way based on his understanding of "chord scales", and intricate improvised solos, frequently across shifting tonal centres. He used myriad scale forms often derived from those such as the Lydian, diminished, harmonic major, augmented, whole tone, chromatic and altered scales, among others, often resulting in an unpredictable and dissonant "outside" sound. His unique legato soloing technique stemmed from his original desire to play the saxophone. Unable to afford one, he strove to use the guitar to create similarly smooth lines of notes. He also became associated with playing an early form of guitar synthesizer called the SynthAxe, a company he endorsed in the 1980s.

Holdsworth has been cited as an influence by a host of rock, metal and jazz guitarists such as Eddie Van Halen, Joe Satriani, Greg Howe, Shawn Lane, Richie Kotzen, John Petrucci, Alex Lifeson, Kurt Rosenwinkel, Yngwie Malmsteen, Michael Romeo, Ty Tabor, Fredrik Thordendal, Daniel Mongrain, John Frusciante, and Tom Morello. Frank Zappa once lauded him as "one of the most interesting guys on guitar on the planet", while Robben Ford has said: "I think Allan Holdsworth is the John Coltrane of the guitar. I don't think anyone can do as much with the guitar as Allan Holdsworth can."