Art rock is a term used by some to describe rock music that is characterized by ambitious, avant-garde or postmodern lyrical themes and/or melodic, harmonic, or rhythmic experimentation, often extending beyond standard pop song forms and genres, toward influences in jazz, classical, world music or the experimental avant-garde. The art rock designation is a vague one, since few rock and pop musicians openly aspire to the title. The concept of "art rock" has also sometimes been conflated with the genre of progressive rock, though today the terms are usually used differently.

The record often cited as the first step towards such experimentation is the Beatles' Sgt. Pepper's Lonely Hearts Club Band (1967), it being an "unabashedly eclectic, musically clever (harmonies, rhythms and, above all, arrangements) melange that could only have been created in the modern recording studio."^{[citation needed]} Art rock may be considered "arty" through imitation of classical "art" music or literature, or simply through eclecticism. Examples of the former include The Moody Blues, The Nice, and Emerson, Lake & Palmer and examples of the latter include Roxy Music, Genesis, Audience and Electric Light Orchestra. (Rockwell 1992, p.492-494)

Taken subjectively, art rock is a term that can encompass just about any style within the rock n' roll umbrella. To name just a few: Brian Eno's ambient music; the avant-garde experimental proto-punk of The Velvet Underground while John Cale was present in the lineup, which actually predates Sgt. Pepper's; the electronica and musique concrete of German Krautrock bands like Can and Neu!; Tool's textured heavy metal; gothic rock founding fathers Bauhaus; Joni Mitchell's jazz-infused folk rock; and the sonic experimentation and/or abrasive noise common to many post-punk, indie, and alternative rock bands of the past 25 years. Around 2004, the phrase "art rock" has been popularly used to describe a movement of bands influenced by the 1970s/1980s work of artists like David Bowie, David Byrne, Tom Verlaine and Brian Eno, such as The Arcade Fire, Broken Social Scene and Wolf Parade.

Critics and fans sometimes use the term 'art rock' to make a cultural statement about the state of popular music. Artists whose sound is based in the rock and pop forms first established in the 1950s and 1960s -- even those who clearly transcend these forms -- are still viewed by certain members of the elite, particularly classical or jazz critics, as mere peddlers of product, and thus 'low art'. Identifying certain popular music as 'art rock' makes a claim both for the integrity of the specified work or artist, and for the serious artistic potential of rock and pop music in general. The term has never come into wide use beyond the world of rock criticism, for perhaps the same reason; most creative bands and popular music artists have no interest themselves in claiming adherence to the rigid standards of those who find little of value in pop music. In fact since the 1960s and 1970s, many of the artists one might class as 'art rock' (along with an increasing consensus among modern cultural elites themselves), actively resist the idea any such thing as 'high art' exists at all, at least as it was formerly defined to exclude most rock and pop music.

Art rock reached its commercial height with the popularity of the aforementioned progressive rock bands, such as King Crimson, Yes, and especially Pink Floyd, whose mix of jazz, classical and blues influences, smooth psychedelic soundscapes, and anti-establishment lyrics proved to be commercially viable as mainstream pop music, and very influential. After the punk revolution of the late '70s put simplicity back in style, and as openly 'progressive' bands drifted toward the mainstream with hit singles and more commercial productions, their 'art rock' designation fell away, and a new breed of artists took their place on the cutting edge of 'art rock'. However, this is not to say that there was any general evolution of the 'art rock' scene, as a scene never existed. Many individual artists with huge variations in sound and popular appeal, and their own allegiance or nonallegiance to varying specific subgenres of rock music, might be designated broadly as 'art rock' by certain publications at certain times, and not designated as such at other times. Artists working in a wide variety of styles continued to be designated occasionally as 'art rock', but by the 1980s, those with influences in noisy punk and innovative electronic music were often more likely to be considered 'art' than those creating epic classical- and jazz-influenced "progressive" compositions.

Though technically one might think of art rock as the antithesis of punk's straightforwardness, most well respected so-called art rock bands of the last 30 years made music influenced by the punk ethic, if not the sound, in some regard. Sonic Youth began as a wildly experimental venture, influenced by the noisiest fringes of punk and the classical avant-garde — especially the guitar works of Glenn Branca; by the late 1980s, their music was accessible enough to influence a new generation of alt rock and grunge bands, like Nirvana. In fact, the webs of connections are so twisted that original progressive rockers King Crimson and new wave punks Talking Heads actually converged on very similar styles of music in the 1980s, even sharing the same guitarist (Adrian Belew). But both groups throughout their varied careers are considered by many to epitomize art rock, as the term refers to a perceived aesthetic or ideology of pop music, rather than a specific musical style.

The use of art in art rock should not be confused with its use in art music, which generally connotes western classical music, not "arty" popular music. However, it must be noted that late 20th-century "classical" composers such as John Cage, Karlheinz Stockhausen, Steve Reich, Terry Riley, and Philip Glass, with their interest in rhythm, repetition, and texture, have come ever closer to bridging the gap with popular music. The only remaining line between certain forms of "art rock" and avant-garde classical is a vague one, with some artists, such as Laurie Anderson, existing right on the boundary. Avant-garde and minimalist music, like other classical music, is still usually composed and written down so that it can be played in concert by various performers, while in art rock, like any other modern pop music, the music is not written down because the primary medium is the original recording, and subsequent live performances are usually done by the songwriters/composers themselves. But even here the line is blurred, since many of these same avant-garde "classical" composers have relied on recorded sound and tape loop or electronic manipulation just as much as any art rock band, or indeed, originated the forms or technologies that were later adopted by these bands. At the same time, rock artists like Frank Zappa have composed well respected works of avant-garde classical music and jazz.

• Rockwell, John. "Art Rock" in Henke, James et al. (Eds.) (1992). The Rolling Stone Illustrated History of Rock and Roll: The Definitive History of the Most Important Artists and Their Music. ISBN 0679737286.