Boys' love (BL), a genre of male-male homoerotic media originating in Japan that is created primarily by and for women, has a robust global fandom. Individuals in the BL fandom may participate in activities such as attending conventions, creating and/or posting to fansites, and creating fan works such as fan fiction and fan art.

In Japan, fans of BL are referred to as fujoshi (腐女子). Translating literally to "rotten woman" or "rotten girl", the term originated as a pejorative for fans of the genre but was later reappropriated by BL fans as a self-deprecating identity label. The term fudanshi (腐男子; lit. "rotten boy") later emerged to describe male fans of BL.

Most BL fans are either teenage girls or young women. The female readership in Thailand is estimated at 80%, and the membership of Yaoi-Con, a convention in San Francisco, is 85% female. It is usually assumed that all female fans are heterosexual, but in Japan there is a presence of lesbian manga authors and lesbian, bisexual, other or questioning female readers. Recent online surveys of English-speaking readers of BL indicate that 50-60% of female readers self-identify as heterosexual. It has been suggested that Western fans may be more diverse in their sexual orientation than Japanese fans and that Western fans are "more likely to link" BL ("Boy's Love") to supporting gay rights. Much like the BL readership base, the majority of BL fanfiction writers are also believed to be heterosexual women. The reasoning behind this trend is sometimes attributed to patriarchy- that women who write BL fanfiction are in fact acting out heterosexual fantasies through these male figures.

Although the genre is marketed at women and girls, gay, bisexual, and even heterosexual men also form part of the readership. In one library-based survey of U.S. yaoi fans, about one quarter of respondents were male; online surveys of Anglophone readers place this percentage at about 10%. Lunsing suggests that younger Japanese gay men who are offended by gay men's magazines' "pornographic" content may prefer to read yaoi instead. That is not to say that the majority of homosexual men are fans of the genre, as some are put off by the feminine art style or unrealistic depictions of homosexual life and instead seek "Gei comi" (Gay comics), manga written by and for homosexual men, as gei comi is perceived to be more realistic. Lunsing notes that some of the narrative annoyances that homosexual men express about yaoi manga, such as rape, misogyny, and an absence of a Western-style gay identity, are also present in gei comi. Some male manga artists have produced yaoi works, using their successes in yaoi to then go on to publish gei comi.

Authors of BL present themselves as "fellow fans" by using dust jacket notes and postscripts to chat to the readers "as if they were her girlfriends" and talk about the creative process in making the manga and what she discovered she liked about the story she wrote.

In the mid-1990s, estimates of the size of the Japanese yaoi fandom were at 100,000-500,000 people; at around that time, the long-running yaoi anthology June had a circulation of between 80,000 and 100,000, twice the circulation of the "best-selling" gay lifestyle magazine Badi. Most Western yaoi fansites "appeared some years later than pages and lists devoted to mainstream anime and manga". As of 1995, they "revolved around the most famous series", such as Ai no Kusabi and Zetsuai 1989; and by the late 1990s, English-speaking websites mentioning yaoi "reached the hundreds". As of 2003, on Japanese-language internet sites, there were roughly equal proportions of sites dedicated to yaoi as there were sites by and for gay men about homosexuality. On 16 November 2003, there were 770,000 yaoi websites. As of April 2005, a search for non-Japanese sites resulted in 785,000 English, 49,000 Spanish, 22,400 Korean, 11,900 Italian and 6,900 Chinese sites. In January 2007, there were approximately five million hits for 'yaoi'. Hisako Miyoshi, the vice editor-in-chief for Libre Publishing's manga division, said in a 2008 interview that although Boys Love is more well known to the general public, the number of readers remains limited, which she attributes to the codified nature of the genre.

Thorn noted that while some fans like both equally, fans tend to either prefer BL or non-BL shōjo manga. and Suzuki noted BL fans have a preference for BL over other forms of pornography, for example, heterosexual love stories in ladies' comics. Jessica Bawens-Sugimoto feels that in general, "slash and yaoi fans are dismissive of mainstream hetero-sexual romance", such as "the notorious pulp Harlequin romances". Deborah Shamoon said that "the borders between yaoi, shōjo manga and ladies' comics are quite permeable", suggesting that fans of BL probably enjoyed both homosexual and heterosexual tales. Kazuma Kodaka, in an interview with Giant Robot, suggested that the Japanese yaoi fandom includes married women who had been her fans since they were in college. Dru Pagliassotti's survey indicates that loyalty to an author is a common factor in readers' purchase decisions. Yōka Nitta has noted a split in what her readers want - her younger readers prefer seeing explicit material, and her older readers prefer seeing romance. There is a perception that the English-speaking yaoi fandom is demanding increasingly explicit content, but that this poses problems for retailers. In 2004, ICv2 noted that fans seemed to prefer buying yaoi online. Andrea Wood suggests that due to restrictions placed on the sale of yaoi, many Western teenage fans seek more explicit titles via scanlations. Dru Pagliassotti notes that the majority of respondents to her survey say that they first encountered BL online, which she links to half of her respondents reporting that they get most of their BL from scanlations. In 2003, there were at least five BL scanlation groups. Japanese fan practices in the mid to late 2000s included the concept of the feeling of moe, which was typically used by male otaku about young female characters prior to this.

Robin Brenner and Snow Wildsmith noted in their survey of American fans that gay and bisexual male fans of yaoi preferred more realistic tales than female fans did.