Alternative rock (also known as alternative music, alt-rock or simply alternative) is a category of rock music that evolved from the independent music underground of the 1970s. Alternative rock acts achieved mainstream success in the 1990s with the likes of the grunge subgenre in the United States, and the Britpop and shoegaze subgenres in the United Kingdom and Ireland. During this period, many record labels were looking for "alternatives", as many corporate rock, hard rock, and glam metal acts from the 1980s were beginning to grow stale throughout the music industry. The emergence of Generation X as a cultural force in the 1990s also contributed greatly to the rise of alternative music.

"Alternative" refers to the genre's distinction from mainstream or commercial rock or pop. The term's original meaning was broader, referring to musicians influenced by the musical style or independent, DIY ethos of late-1970s punk rock. Traditionally, alternative rock varied in terms of its sound, social context, and regional roots. Throughout the 1980s, magazines and zines, college radio airplay, and word of mouth had increased the prominence and highlighted the diversity of alternative rock's distinct styles (and music scenes), such as noise pop, indie rock, grunge, and shoegaze. In September 1988, Billboard introduced "alternative" into their charting system to reflect the rise of the format across radio stations in the United States by stations like KROQ-FM in Los Angeles and WDRE-FM in New York, which were playing music from more underground, independent, and non-commercial rock artists.

Initially, several alternative styles achieved minor mainstream notice and a few bands, such as R.E.M. and Jane's Addiction, were signed to major labels. Most alternative bands at the time, like the Smiths, one of the key British alternative rock bands during the 1980s, remained signed to independent labels and received relatively little attention from mainstream radio, television, or newspapers. With the breakthrough of Nirvana and the popularity of the grunge and Britpop movements in the 1990s, alternative rock entered the musical mainstream, and many alternative bands became successful.

Emo found mainstream success in the 2000s with multi-platinum acts such as Fall Out Boy, My Chemical Romance, Paramore and Panic! at the Disco. Bands such as the White Stripes and the Strokes found commercial success in the early 2000s, influencing an influx of new alternative rock bands that drew inspiration from garage rock, post-punk and new wave, establishing a revival of the genres.