Punk rock (also known as punk) is a subgenre of rock music that emerged in the mid-1970s. Rooted in 1950s rock and roll and 1960s garage rock, punk bands rejected the overproduction and corporate nature of mainstream rock music. Typically producing short, fast-paced songs with rough stripped-down vocals and instrumentation and an anti-establishment theme, artists embrace a DIY ethic with many bands self-producing and distributing recordings through independent labels.

During the early 1970s, the term "punk rock" was originally used by some American rock critics to describe mid-1960s garage bands. Subsequent developments such as glam and pub rock in the UK, alongside the Velvet Underground and the New York Dolls from New York have been cited as key influences. By the mid-1970s, the term "punk rock" had become associated with several regional underground music scenes, including the MC5 and the Stooges in Detroit; Television, Patti Smith, Suicide, the Dictators, Richard Hell and the Voidoids, and the Ramones in New York City; Rocket from the Tombs, Electric Eels and Dead Boys in Ohio; the Saints and Radio Birdman in Australia; and the Sex Pistols, the Clash, the Damned and the Buzzcocks in England. By late 1976, punk had become a major cultural phenomenon in the UK, giving rise to a punk subculture that expressed youthful rebellion through distinctive styles of clothing, such as T-shirts with deliberately offensive graphics, leather jackets, studded or spiked bands, jewelry, bondage clothing and safety pins.

By 1977, the influence of punk music and its associated subculture spread worldwide, taking root in a wide range of local scenes. The movement later proliferated into various subgenres during the late 1970s, giving rise to movements such as post-punk, new wave, and art punk. By the early 1980s, punk experienced further diversification with subgenres such as hardcore punk (e.g. Bad Brains, Minor Threat and Black Flag); Oi!, (e.g. Sham 69 and the Exploited); street punk (e.g. GBH, the Partisans, and Chaos UK); and anarcho-punk (e.g. Crass). The movement expanded through several regional scenes in countries such as Japan, the Netherlands, Germany, Spain, Estonia, Greece, and Yugoslavia, among others, and inspired the development of pop-punk, grunge, riot grrrl and alternative rock.

Following alternative rock's mainstream breakthrough in the 1990s through the success of bands like Nirvana, punk rock saw renewed major-label interest and mainstream appeal exemplified by the rise of Californian bands Green Day, Social Distortion, Rancid, the Offspring, Bad Religion, Blink-182 and NOFX.

The first wave of punk rock was "aggressively modern" and differed from what came before. According to Ramones drummer Tommy Ramone, "In its initial form, a lot of 1960s stuff was innovative and exciting. Unfortunately, what happens is that people who could not hold a candle to the likes of Hendrix started noodling away. Soon you had endless solos that went nowhere. By 1973, I knew that what was needed was some pure, stripped down, no bullshit rock 'n' roll." John Holmstrom, founding editor of Punk magazine, recalls feeling "punk rock had to come along because the rock scene had become so tame that [acts] like Billy Joel and Simon and Garfunkel were being called rock and roll, when to me and other fans, rock and roll meant this wild and rebellious music." According to Robert Christgau, punk "scornfully rejected the political idealism and Californian flower-power silliness of hippie myth."

Hippies were rainbow extremists; punks are romantics of black-and-white. Hippies forced warmth; punks cultivate cool. Hippies kidded themselves about free love; punks pretend that s&m is our condition. As symbols of protest, swastikas are no less fatuous than flowers.

Technical accessibility and a do it yourself (DIY) spirit are prized in punk rock. UK pub rock from 1972 to 1975 contributed to the emergence of punk rock by developing a network of small venues, such as pubs, where non-mainstream bands could play. Pub rock also introduced the idea of independent record labels, such as Stiff Records, which put out basic, low-cost records. Pub rock bands organized their own small venue tours and put out small pressings of their records. In the early days of punk rock, this DIY ethic stood in marked contrast to what those in the scene regarded as the ostentatious musical effects and technological demands of many mainstream rock bands. Musical virtuosity was often looked on with suspicion. According to Holmstrom, punk rock was "rock and roll by people who didn't have very many skills as musicians but still felt the need to express themselves through music". In December 1976, the English fanzine Sideburns published a now-famous illustration of three chords, captioned "This is a chord, this is another, this is a third. Now form a band".

British punk rejected contemporary mainstream rock, the broader culture it represented, and their musical predecessors: "No Elvis, Beatles or the Rolling Stones in 1977", declared the Clash song "1977". 1976, when the punk revolution began in Britain, became a musical and a cultural "Year Zero". As nostalgia was discarded, many in the scene adopted a nihilistic attitude summed up by the Sex Pistols' slogan "No Future"; in the later words of one observer, amid the unemployment and social unrest in 1977, "punk's nihilistic swagger was the most thrilling thing in England." While "self-imposed alienation" was common among "drunk punks" and "gutter punks", there was always a tension between their nihilistic outlook and the "radical leftist utopianism" of bands such as Crass, who found positive, liberating meaning in the movement. As a Clash associate describes singer Joe Strummer's outlook, "Punk rock is meant to be our freedom. We're meant to be able to do what we want to do."