Which of these categories a particular work falls into is largely defined by the intent and self-definition of the work by its creator. The formal distinction may be that the rock opera tells a coherent (if often sketchy) story and a concept album sets a mood or maintains a theme, but some albums share aspects of both of these cases. The rock musical is generally first performed as a theatrical production rather than appearing as an album, has little or no identification with a particular band and a generally stronger air of show business. The categories are flexible, to say the least.

Pete Townshend, both with and without his band The Who, is arguably the single artist most associated with the term "rock opera". The earliest example of the form was seen in the track "A Quick One While He's Away" from The Who's second album, A Quick One (Happy Jack) (1966), a nine-minute suite of song snippets telling an operatic story. In 1968 The Pretty Things released S.F. Sorrow, thought to be the first attempt at a single thematic concept expressed over an album's worth of songs. Less than a year later The Who returned with Tommy, the first album explicitly billed as a rock opera. Tommy remains the most famous rock opera, with concert, film and theatrical productions mounted over the course of three decades. The Who would later release Quadrophenia, also made into a film.

Examples of rock operas include:

• Pretty Things, S.F. Sorrow: Either the first rock opera or the first concept album
• The Who, Tommy (1969): The album which arguably popularized the term "rock opera"
• The Who, Quadrophenia (1973)
• Pete Townshend, White City (1986): Subtitled "A novel", a video was released in conjunction with this album.
• Pete Townshend, The Iron Man (1989): A "musical" based on Ted Hughes' book The Iron Man (which was also the basis for the animated film The Iron Giant)
• Pete Townshend, Psychoderelict (1993): An album of linked songs with dialogue advancing the story between the music, a version without the dialogue was also released
• Spock's Beard, Snow (2002): Has a storyline and themes very similar to The Who's Tommy
• David Bowie, The Rise And Fall Of Ziggy Stardust And The Spiders From Mars
• Pink Floyd, The Wall (1978)
• Tim Rice and Andrew Lloyd Webber, Jesus Christ Superstar: Considered a rock musical
• Godspell: Also a rock musical
• Moulin Rouge: A stretch, uses a collection of rock songs from many sources to tell a story.
• Meat Loaf, Bat out of Hell and Bat out of Hell II: Back Into Hell
• Styx, Kilroy was Here (1983)
• The Kinks, Preservation Act 1, Preservation Act 2, A Soap Opera, and Schoolboys in Disgrace
• Genesis, The lamb lies down on Broadway: Famous prog-rock opera.