Riot grrrl is an underground feminist punk movement that began during the early 1990s within the United States in Olympia, Washington, and the greater Pacific Northwest, and has expanded to at least 26 other countries. A subcultural movement that combines feminism, punk music, and politics, it is often associated with third-wave feminism, which is sometimes seen as having grown out of the riot grrrl movement and has recently been seen in fourth-wave feminist punk music that rose in the 2010s. It has also been described as a genre that came out of indie rock, with the punk scene serving as an inspiration for a movement in which women could express anger, rage, and frustration, emotions considered socially acceptable for male songwriters but less commonly for women.

Riot grrrl songs often address issues such as rape, domestic abuse, sexuality, racism, patriarchy, classism, anarchism, and female empowerment. Primary bands most associated with the movement by media include Bikini Kill, Bratmobile, Heavens to Betsy, Excuse 17, Slant 6, Emily's Sassy Lime, Huggy Bear, Jack Off Jill and Skinned Teen. Also included are queercore groups such as Team Dresch and the Third Sex.

In addition to a unique music scene and genre, riot grrrl became a subculture involving a DIY ethic, zines, art, political action, and activism. The movement quickly spread well beyond its musical roots to influence the vibrant zine- and Internet-based nature of fourth-wave feminism, complete with local meetings and grassroots organizing to end intersectional forms of prejudice and oppression, especially physical and emotional violence against all genders.

The riot grrrl movement originated in 1991, when a group of women from Olympia, Washington, and Washington, D.C., held a meeting about sexism in their local punk scenes in the United States. The word "girl" was intentionally used in order to focus on childhood, a time when children have the strongest self-esteem and belief in themselves. Riot grrrls then took a growling "R", replacing the "I" in the word as a way to take back the derogatory use of the term. Both double and triple "R" spellings are acceptable.

The Seattle and Olympia, Washington, music scenes in the Pacific Northwest had sophisticated do it yourself (DIY) infrastructure. Women involved in local underground music scenes took advantage of this platform to articulate their feminist beliefs and desires by creating zines. While the model of politically themed zines had already been used in punk culture as an alternative (to mainstream) culture, zines also followed a longer legacy of self-published feminist writing that allowed women to circulate ideas that would not otherwise be published. At the time there was discomfort among many women in the music scene who felt that they had no space for organizing due to the exclusionary, male-dominated nature of punk culture at the time. Many women found that while they identified with the larger, music-oriented subculture of punk rock, they often had little to no voice in their local scenes. Women in the Washington punk scenes took it upon themselves to represent their own interests artistically through the new riot grrrl subculture. To quote Liz Naylor, who would become the manager of English riot grrrl band Huggy Bear:

There was a lot of anger and self-mutilation. In a symbolic sense, women were cutting and destroying the established image of femininity, aggressively tearing it down.

Riot grrrl bands were influenced by groundbreaking female punk and mainstream rock performers of the 1970s to the mid-1980s. While many of these musicians were not originally associated with each other during their time and came from a variety of backgrounds and styles, as a group they anticipated many of riot grrrl's musical and thematic attributes. These performers include the Slits, Poly Styrene, Siouxsie Sioux, the Raincoats, Joan Jett, Kim Gordon, and Kim Deal, among others. Of Kim Gordon, in particular, Kathleen Hanna noted, "She was a forerunner, musically [...] Just knowing a woman was in a band trading lead vocals, playing bass, and being a visual artist at the same time made me feel less alone." Riot grrrl musicians and musicians-to-be were also inspired by the 1982 U.S. musical drama movie Ladies and Gentlemen, The Fabulous Stains, which tells the story of a (fictional) seemingly proto-riot grrrl band.

Olympia, Washington, had a strong feminist artistic and cultural legacy that influenced early riot grrrl. In the early 1980s, Stella Marrs, Dana Squires and Julie Fay co-founded the store Girl City, where they created art and performances. The first K Records release in 1982 was a cassette of Heather Lewis' first band Supreme Cool Beings, while she was a student at The Evergreen State College, a year before she co-founded Beat Happening. In 1985, the Go Team formed with then 15-year-old Tobi Vail. The band would go on to collaborate with Olympia scene musicians who are linked to the riot grrrl movement: Donna Dresch, Lois Maffeo, and Billy "Boredom" Karren. Karren was a rotating musician who played in the band, and it was there that he and Vail played together for the first time, later collaborating in several other bands which included Bikini Kill and the Frumpies. Maffeo hosted a women-centered radio show on Olympia's community radio station KAOS. Candice Pedersen interned at K Records in 1986 while at The Evergreen State College, and became co-owner in 1989.