Kathleen Hanna (born November 12, 1968) is an American singer, musician and pioneer of the feminist punk riot grrrl movement, and punk zine writer. She is the lead singer of feminist punk band Bikini Kill and fronted the electropunk band Le Tigre in the late 1990s and early 2000s. Since 2010, she has recorded as the Julie Ruin.

In 2009, Hanna made her zines, art pieces, photography, video, music, journals, and other material which focus on the early formation of the Riot Grrrl movement available at the Fales Library at New York University. A documentary film about Hanna was released in 2013 by director Sini Anderson, titled The Punk Singer, detailing Hanna's life and career, as well as revealing her years-long battle with Lyme disease. Hanna is married to Adam Horovitz of the Beastie Boys.

Hanna was born November 12, 1968, in Portland, Oregon. At age three, her family moved to Calverton, Maryland; as Hanna's father changed occupations, the family moved several more times. Hanna first became interested in feminism around the age of nine, after her mother took her to a rally in Washington, D.C. where feminist icon Gloria Steinem spoke. In a 2000 interview with BUST magazine, Hanna recalled: "My mom was a housewife and wasn't somebody that people would think of as a feminist, and when Ms. magazine came out we were incredibly inspired by it. I used to cut pictures out of it and make posters that said 'Girls can do anything', and stuff like that, and my mom was inspired to work at a basement of a church doing anti-domestic violence work. Then she took me to the Solidarity Day thing, and it was the first time I had ever been in a big crowd of women yelling, and it really made me want to do it forever."

Hanna's interest grew when her mother checked out a copy of Betty Friedan's The Feminine Mystique from the library. Their involvement in the women's rights movement was done quietly during Hanna's childhood, due to her father's disapproval.

Upon her parents' divorce, Hanna returned to Portland and attended Lincoln High School and Grant High School. After high school, she relocated from Portland to Olympia, Washington, to attend The Evergreen State College in the late 1980s. During this time she worked as a stripper to pay her tuition. "My parents didn't go to college. I felt lucky [to attend]." While at Evergreen, with fellow student and photographer Aaron Baush-Greene, she set up a photo exhibit featuring the pair's photography, which dealt with sexism, violence against women, and AIDS – issues that were heightened for Hanna when she volunteered for SafePlace, a domestic violence organization. However, the school administrators took the photos down before they had the chance to be viewed, an act of censorship that prompted what Hanna refers to as her "first foray into activism": the creation of Reko Muse, an independent feminist art gallery, with friends Heidi Arbogast and Tammy Rae Carland.

Hanna began doing spoken word performances that addressed sexism and violence against women. Eventually, she abandoned spoken word in favor of music after a conversation with one of her favorite writers, countercultural icon Kathy Acker. Hanna recalled,

Acker asked me why writing was important to me, and I said, 'Because I felt like I'd never been listened to and I had a lot to say,' and she said, 'Then why are you doing spoken word—no one goes to spoken word shows! You should get in a band.'

Hanna then formed a band with Arbogast and Carland, called "Amy Carter", which put on shows before the art exhibitions.