John Martin Marr is a musician, songwriter and singer. He first achieved fame as the guitarist and co-songwriter of the Smiths, who were active from 1982 to 1987. He has since performed with numerous other bands and embarked on a solo career.

The Smiths were an English rock band formed in Manchester in 1982, composed of the singer Morrissey, the guitarist Johnny Marr, the bassist Andy Rourke, and the drummer Mike Joyce. Morrissey and Marr formed the band's songwriting partnership. The Smiths are regarded as one of the most important acts to emerge from 1980s British independent music.