In Japanese popular culture, lolicon (ロリコン, rorikon) is a genre of fictional media which focuses on young or young-looking girl characters, particularly in a sexually suggestive or erotic manner. The term, a portmanteau of the English-language phrase "Lolita complex", also refers to desire and affection for such characters (ロリ, "loli"), and their fans. Associated mainly with stylized imagery in manga, anime, and video games, lolicon in otaku culture is generally understood as distinct from desires for realistic depictions of young girls, or real young girls as such, and is associated with moe, or affection for fictional characters, often bishōjo (cute girl) characters in manga or anime.

The phrase "Lolita complex", derived from the novel Lolita, entered use in Japan in the 1970s. During the "lolicon boom" in erotic manga of the early 1980s, the term was adopted in the nascent otaku culture to denote attraction to early bishōjo characters, and later only to younger-looking depictions as bishōjo designs became more varied. The artwork of the lolicon boom, which was strongly influenced by the styles of shōjo manga, marked a shift from realism, and the advent of "cute eroticism" (kawaii ero), an aesthetic which is now common in manga and anime broadly. The lolicon boom faded by the mid-1980s, and the genre has since made up a minority of erotic manga.

Since the 1990s, lolicon has been a keyword in manga debates in Japan and globally. Child pornography laws in some countries apply to depictions of fictional child characters, while those in other countries, including Japan, do not. Opponents and supporters have debated if the genre contributes to child sexual abuse. Culture and media scholars generally identify lolicon with a broader separation between fiction and reality within otaku sexuality.

Lolicon is a Japanese abbreviation of "Lolita complex" (ロリータ・コンプレックス, rorīta konpurekkusu), an English-language phrase derived from Vladimir Nabokov's novel Lolita (1955) and introduced to Japan in Russell Trainer's The Lolita Complex (1966, translated 1969), a work of pop psychology in which it is used to denote attraction to pubescent and pre-pubescent girls. In Japanese, the phrase was adopted to describe feelings of love and lust for young girls over adult women, which remains the term's common meaning. Due to its association with otaku culture, the term is more often used to describe desires for young or young-looking girl characters (ロリ, "loli") in manga or anime, which are generally understood to exist within fiction. However, the meaning of the term remains contested, and it carries a connotation of pedophilia for much of the public. Lolicon also refers to works, particularly sexually suggestive or erotic, which feature such characters, and their fans. Lolicon is distinct from words for pedophilia (yōji-zuki and pedofiria; clinically, shōniseiai and jidōseiai) and for child pornography (jidō poruno).

The meaning of lolicon within the otaku context developed in the early 1980s, during the "lolicon boom" in erotic manga (see § History). According to Akira Akagi, the meaning of lolicon moved away from the sexual pairing of an older man and a young girl, and instead came to describe desire for "cuteness" and "girl-ness" in manga and anime. Others defined lolicon as a desire for "cute things", "manga-like" or "anime-like" characters, "roundness", and the "two-dimensional" as opposed to the "real". At the time, all eroticism in the manga style featuring bishōjo (cute girl) characters was associated with the term, and synonyms of "Lolita complex" included "two-dimensional complex" (nijigen konpurekkusu), "two-dimensional fetishism" (nijikon fechi), "two-dimensional syndrome" (nijikon shōkōgun), "cute girl syndrome" (bishōjo shōkōgun), and simply "sickness" (byōki). As character body types within erotic manga became more varied by the end of the lolicon boom in 1984, the scope of the term narrowed to younger-looking depictions.

Lolicon became a buzz word after the 1989 arrest of Tsutomu Miyazaki, a serial killer of young girls who was portrayed by the Japanese media as an otaku (see § History). As lolicon was conflated with pedophilia in the public debates on "harmful manga", its meaning was replaced among otaku by moe, which refers to feelings of affection for characters more generally. Like moe, lolicon is still used by many otaku to refer to attraction which is consciously distinct from reality; some otaku identify as "two-dimensional lolicon" (nijigen rorikon) to specify their attraction to characters. The term has become a keyword in criticism of manga and sexuality within Japan, as well as globally with the spread of Japanese popular culture.

In the 1970s, shōjo manga (marketed to girls and young adult women) underwent a renaissance in which artists, such as those of the Year 24 Group, experimented with new narratives and styles, and introduced themes such as psychology, gender, and sexuality. These developments attracted adult male fans of shōjo manga, who crossed gendered boundaries to produce and consume it. The first appearance of the term "Lolita complex" in manga was in Stumbling Upon a Cabbage Patch, an Alice in Wonderland–inspired work by Shinji Wada published in a 1974 issue of the shōjo manga magazine Bessatsu Margaret, where a male character calls Lewis Carroll a man with a "strange character of liking only small children" in an inside joke to adult readers. Early lolicon artwork was influenced by male artists mimicking shōjo manga, as well as erotic manga created by female artists for male readers.

The image of the shōjo (young girl) rose to prominence in Japanese mass media in the 1970s as a symbol of cuteness, innocence, and an "idealized Eros", attributes which became attached to imagery of younger girls over time. Nude photographs of shōjo, conceived as fine art, gained popularity: a photo collection titled Nymphet: The Myth of the 12-Year-Old was published in 1969, and in 1972 and 1973 there was an "Alice boom" in nude photos themed around Alice in Wonderland. Specialty adult magazines carrying nude photos, fiction, and essays on the appeal of young girls emerged in the 1980s; this trend faded in the late 1980s, due to backlash and because many men preferred images of shōjo in manga and anime. The spread of such imagery, both in photographs and in manga, may have been helped by prohibitions on displaying pubic hair under Japan's obscenity laws.