J-pop (often stylized in all caps; an abbreviated form of "Japanese popular music"), natively known simply as pops (ポップス, poppusu), is the name for a form of popular music that entered the musical mainstream of Japan in the 1990s. Modern J-pop has its roots in traditional music of Japan, and significantly in 1960s pop and rock music. J-pop replaced kayōkyoku ("Lyric Singing Music"), a term for Japanese popular music from the 1920s to the 1980s in the Japanese music scene.

Japanese rock bands such as Happy End fused the Beatles and Beach Boys-style rock with Japanese music in the 1960s–1970s. J-pop was further defined by new wave and crossover fusion acts of the late 1970s, such as Yellow Magic Orchestra and Southern All Stars. Popular styles of Japanese pop music include city pop and technopop during the 1970s–1980s, and J-Euro (such as Namie Amuro) and Shibuya-kei during the 1990s and 2000s.

Japanese country had popularity during the international popularity of Westerns in the 1960s–1970s as well, and it still has appeal due to the work of musicians like Charlie Nagatani and Tomi Fujiyama, along with venues like Little Texas in Tokyo. Japanese hip hop became mainstream with producer Nujabes during the 1990s–2000s, especially his work on Samurai Champloo, and Japanese pop culture is often seen with anime in hip hop. In addition, Latin music, CCM, and gospel music have scenes within J-pop.

The origin of modern J-pop is said to be Japanese-language rock music inspired by the likes of The Beatles. Unlike the Japanese music genre called kayōkyoku, J-pop uses a special kind of pronunciation, which is similar to that of English. One notable singer to do so is Keisuke Kuwata, who pronounced the Japanese word karada ("body") as kyerada. Additionally, unlike Western music, the major second (sol and la) was usually not used in Japanese music, except art music, before rock music became popular in Japan. When the Group Sounds genre, which was inspired by Western rock, became popular, Japanese pop music adopted the major second, which was used in the final sounds of The Beatles' song "I Want to Hold Your Hand" and The Rolling Stones' song "(I Can't Get No) Satisfaction". Although Japanese pop music changed from music based on Japanese pentatonic scale and distortional tetrachord to the more occidental music over time, music that drew from the traditional Japanese singing style remained popular (such as that of Ringo Shiina).

At first, the term J-pop was used only for Western-style musicians in Japan, such as Pizzicato Five and Flipper's Guitar, just after Japanese radio station J-Wave was established. On the other hand, Mitsuhiro Hidaka of AAA from Avex Trax said that J-pop was originally derived from the Eurobeat genre. However, the term became a blanket term, covering other music genres—such as the majority of Japanese rock music of the 1990s.

In 1990, the Japanese subsidiary of Tower Records defined J-pop as all Japanese music belonging to the Recording Industry Association of Japan except Japanese independent music (which they term "J-indie"); their stores began to use additional classifications, such as J-club, J-punk, J-hip-hop, J-reggae, J-anime, and Visual kei by 2008, after independent musicians started to release works via major labels. Ito Music City, a Japanese record store, adopted expanded classifications including Group Sounds, idol of the 1970s–1980s, enka, folk and established musicians of the 1970s–1980s, in addition to the main J-pop genres.

Whereas rock musicians in Japan usually hate the term "pop", Taro Kato, a member of pop punk band Beat Crusaders, pointed out that the encoded pop music, like pop art, was catchier than "J-pop" and he also said that J-pop was the pops (ポップス, poppusu) music, memorable for its frequency of airplay, in an interview when the band completed their first full-length studio album under a major label, P.O.A.: Pop on Arrival, in 2005. Because the band did not want to perform J-pop music, their album featured the 1980s Pop of MTV. According to his fellow band member Toru Hidaka, the 1990s music that influenced him (such as Nirvana, Hi-Standard, and Flipper's Guitar) was not listened to by fans of other music in Japan at that time.

In contrast to this, although many Japanese rock musicians until the late 1980s disrespected the kayōkyoku music, many of Japanese rock bands of the 1990s—such as Glay—assimilated kayōkyoku into their music. After the late 1980s, breakbeat and samplers also changed the Japanese music scene, where expert drummers had played good rhythm because traditional Japanese music did not have the rhythm based on rock or blues.