Power pop (also typeset as powerpop) is a subgenre of rock music and a form of pop rock based on the early music of bands such as the Who, the Beatles, the Beach Boys, and the Byrds. It typically incorporates melodic hooks, vocal harmonies, an energetic performance, and cheerful-sounding music underpinned by a sense of yearning, longing, despair, or self-empowerment. The sound is primarily rooted in pop and rock traditions of the early-to-mid 1960s, although some artists have occasionally drawn from later styles such as punk, new wave, glam rock, pub rock, college rock, and neo-psychedelia.

Originating in the 1960s, power pop developed mainly among American musicians who came of age during the British Invasion. Many of these young musicians wished to retain the "teenage innocence" of pop and rebelled against newer forms of rock music that were thought to be pretentious and inaccessible. The term was coined in 1967 by the Who guitarist and songwriter Pete Townshend to describe his band's style of music. However, power pop became more widely identified with later acts of the 1970s who sought to revive Beatles-style pop. Early 1970s releases by Badfinger, the Raspberries, Big Star and Todd Rundgren are sometimes credited with solidifying the power pop sound into a recognizable genre. Power pop reached its commercial peak during the rise of punk and new wave in the late 1970s, with Cheap Trick, the Knack, the Romantics, Nick Lowe, Dave Edmunds, and Dwight Twilley among those enjoying the most success. After a popular and critical backlash to the genre's biggest hit, "My Sharona" (the Knack, 1979), record companies generally stopped signing power pop groups, and most of the 1970s bands broke up in the early 1980s.

Over subsequent decades, power pop continued with modest commercial success while also remaining a frequent object of derision among some critics and musicians. The 1990s saw a new wave of alternative bands that were drawn to 1960s artists because of the 1980s music they had influenced. Although not as successful as their predecessors, Jellyfish, the Posies, Redd Kross, Teenage Fanclub, and Material Issue were critical and cult favorites. In the mid-1990s, an offshoot genre that combined power pop-style harmonies with uptempo punk rock, dubbed "pop-punk", reached mainstream popularity.

Power pop is an energetic variant of pop rock based on melodic hooks, encapsulated as "catchy tunes with an attitude". AllMusic describes the style as "a cross between the crunching hard rock of the Who and the sweet melodicism of the Beatles and the Beach Boys, with the ringing guitars of the Byrds thrown in for good measure". Virtually every artist of the genre has been a rock band consisting of white male musicians who engaged with the song forms, vocal arrangements, chord progressions, rhythm patterns, instrumentation, or overall sound associated with groups of the mid-1960s British Invasion era.

An essential feature of power pop is that its cheerful sounding arrangements are supported by a sense of "yearning", "longing", or "despair" similar to formative works such as "Wouldn't It Be Nice" (the Beach Boys, 1966) and "Pictures of Lily" (the Who, 1967). This might be achieved with an unexpected harmonic change or lyrics that refer to "tonight", "tomorrow night", "Saturday night", and so on. Power pop was also noted for its lack of irony and its reverence to classic pop craft.

The Who's Pete Townshend coined the term in a May 1967 interview promoting their latest single "Pictures of Lily". He said: "Power pop is what we play—what the Small Faces used to play, and the kind of pop the Beach Boys played in the days of 'Fun, Fun, Fun' which I preferred." Despite other bands following in the power pop continuum since then, the term was not popularized until the rise of new wave music in the late 1970s. Greg Shaw, editor of Bomp! magazine, was the most prominent in the slew of music critics that wrote about power pop (then written as "powerpop"). This mirrored similar developments with the term "punk rock" from earlier in the decade. In light of this, Theo Cateforis, author of Are We Not New Wave? (2011), wrote that "the recognition and formulation" of power pop as a genre "was by no means organic."

There is significant debate among fans over what should be classed as power pop. Shaw took credit for codifying the genre in 1978, describing it as a hybrid style of pop and punk. He later wrote that "much to my chagrin, the term was snapped up by legions of limp, second-rate bands hoping the majors would see them as a safe alternative to punk." Music journalist John M. Borack also stated in his 2007 book Shake Some Action – The Ultimate Guide to Power Pop that the label is often applied to varied groups and artists with "blissful indifference", noting its use in connection with Britney Spears, Green Day, the Bay City Rollers and Def Leppard.

Power pop has struggled with its critical reception and is sometimes viewed as a shallow style of music associated with teenage audiences. The perception was exacerbated by record labels in the early 1980s who used the term for marketing post-punk styles. Music critic Ken Sharp summarized that power pop is "the Rodney Dangerfield of rock 'n' roll. [...] the direct updating of the most revered artists—the Who, the Beach Boys, the Beatles—yet it gets no respect." In 1996, singer-songwriter Tommy Keene commented that any association to the term since the 1980s is to be "compared to a lot of bands that didn't sell records, it's like a disease. If you're labeled that, you're history." Musician Steve Albini said: "I cannot bring myself to use the term 'power pop.' Catchy, mock-descriptive terms are for dilettantes and journalists. I guess you could say I think this music is for pussies and should be stopped." Ken Stringfellow of the Posies concurred that "There's a kind of aesthetic to power pop to be light on purpose. I wanted something with more gravitas."