Thin Lizzy are a hard rock band formed in Dublin, Ireland, in 1969. Their music reflects a wide range of influences, including blues, soul music, psychedelic rock, and traditional Irish folk music, but is generally classified as hard rock or sometimes heavy metal.

Two of the founding members, drummer Brian Downey and bass guitarist and lead vocalist Phil Lynott, met while still in school. Lynott led the group throughout their recording career of twelve studio albums, writing most of the material. The singles "Whiskey in the Jar" (a traditional Irish ballad), "The Boys Are Back in Town" and "Waiting for an Alibi" were international hits. After Lynott's death in 1986, various incarnations of the band emerged over the years based initially around guitarists Scott Gorham and John Sykes, though Sykes left the band in 2009. Gorham later continued with a new line-up including Downey. In 2012, Gorham and Downey decided against recording new material as Thin Lizzy so a new band, Black Star Riders, was formed to tour and produce new releases such as their debut album All Hell Breaks Loose. Thin Lizzy plan to reunite for occasional concerts.

Lynott, Thin Lizzy's de facto leader, was composer or co-composer of almost all of the band's songs, and the first black Irishman to achieve commercial success in the field of rock music. Thin Lizzy featured several guitarists throughout their history, with Downey and Lynott as the rhythm section, on the drums and bass guitar. As well as being multiracial, the band drew their early members not only from both sides of the Irish border but also from both the Catholic and Protestant communities during The Troubles.

Rolling Stone magazine describes the band as distinctly hard rock, "far apart from the braying mid-70s metal pack". AllMusic critic John Dougan has written that "As the band's creative force, Lynott was a more insightful and intelligent writer than many of his ilk, preferring slice-of-life working-class dramas of love and hate influenced by Bob Dylan, Bruce Springsteen, and virtually all of the Irish literary tradition."