Indie rock is a sub-genre of alternative rock that originated in the United Kingdom and the United States in the 1980s. The meaning of the term "indie rock" is contested today by many musicians, fans and commentators. Most use the term "indie" to describe any rock music produced by artists working within the network of independent record labels and underground music venues that emerged in the United States and elsewhere in 1980s and 1990s. Others see indie rock as a distinct genre of rock music with a specific artistic aesthetic, and care less about the context in which it is made. Many embrace both meanings of the word, believing that the aesthetics of the genre and its means of production are deeply intertwined.

Indie rock artists are known for placing a premium on maintaining complete control of their music and careers, releasing albums on independent record labels and relying on touring, word-of-mouth, airplay on independent or college radio stations and, in recent years, the Internet for promotion. However, in the 2000s many acts with a musical style identified as "indie" signed to major record labels or their subsidiaries, and began promoting themselves through more traditional media outlets. This has led to a further blurring in the meaning of the term.

In the 1980s, alternative rock, used as a term, was more or less synonymous with indie rock. In the United States, the term "indie rock" was particularly associated with the abrasive, distortion-heavy sounds of Hüsker Dü, Sonic Youth, Minutemen, Meat Puppets, Dinosaur Jr., Pixies and The Replacements. R.E.M. is often associated with the college rock movement of the 1980s. In the United Kingdom, indie pop artists such as Aztec Camera, Josef K, and Orange Juice emerged in the 1980s. The Smiths have been seen as the defining British indie-rock band of the '80s. This era also saw the birth of the C86 indie-pop movement and the twee pop of Sarah Records artists. A number of prominent indie rock record labels were founded during the 1980s. These include Washington, DC's Dischord Records in 1980, Seattle's Sub Pop Records in 1986 and New York City's Matador Records and Durham, North Carolina's Merge Records in 1989. Chicago's Touch and Go Records was founded as a fanzine in 1979 and began to release records during the 1980s.

The 1990s brought major changes to the alternative rock scene. Grunge bands such as Nirvana, Alice in Chains, Soundgarden and Pearl Jam broke into the mainstream, achieving commercial chart success and widespread exposure. Punk revival bands like Green Day and The Offspring also became popular and were grouped under the "alternative" umbrella. The meaning of the term "alternative" changed as mainstream success attracted major-label investment and commercially-oriented or manufactured acts with a formulaic, conservative approach. With this, "alternative" lost its original counter-cultural meaning and began to refer to the new form of music that was now achieving mainstream success. The term "indie rock" became associated with the bands and genres that remained underground.

In the 2000s, the changing music industry and increased use of the internet as a tool for music promotion allowed a number of indie rock bands to achieve mainstream commercial success. Modest Mouse was one of the first popular indie acts of the 1990s to make the jump to a major label, signing with Epic Records in 2000. Their 2004 album Good News for People Who Love Bad News was nominated for a Grammy Award for Best Alternative Rock Album. After many years with the Barsuk label, Death Cab for Cutie signed to Atlantic Records in 2004. Their 2005 album Plans was nominated for the Grammy Award for Best Alternative Album of that year and charted on the Billboard charts for 47 consecutive weeks and attained Platinum sales. In November 2004, two Bright Eyes singles, "Lua" and "Take It Easy (Love Nothing)", reached the two top spots on the Billboard Hot 100 Single Sales. In 2010, Arcade Fire's album The Suburbs reached number 1 on the Billboard charts in the United States and the United Kingdom. The following February the group won one Grammy Award (out of three nominations) for Album of The Year. The Walkmen, LCD Soundsystem, Vampire Weekend, The Black Keys, Interpol, Spoon, Grizzly Bear, and The National have also enjoyed mainstream popularity. Reasons suggested for this success include the decline of record sales and increased media exposure of indie artists due to internet marketing.