Martin Lancelot Barre (; born 17 November 1946) is an English rock musician best known for his work as lead guitarist with progressive rock band Jethro Tull, with whom he recorded and toured from their second album in 1969 to the band's initial dissolution in 2012.
In the early 1990s he went solo, and has recorded four studio albums and made several guest appearances.
He has also played the flute and other instruments such as the mandolin, both on stage for Jethro Tull and in his own solo work.