Kathryn Ann Bigelow (/ˈbɪɡəˌloʊ/; born November 27, 1951) is an American film director, producer, and screenwriter. Her accolades include two Academy Awards, two BAFTA Awards, and a Primetime Emmy Award. Time magazine named her one of the 100 most influential people in the world in 2010.

Bigelow made her directorial film debut with the outlaw biker film The Loveless (1981). She rose to prominence directing the thrillers Near Dark (1987), Blue Steel (1990), Point Break (1991), Strange Days (1995), and K-19: The Widowmaker (2002). For directing the war drama The Hurt Locker (2008), Bigelow became the first woman to win the Academy Award for Best Director. She has since directed the spy thriller Zero Dark Thirty (2012), and the crime drama Detroit (2017).

She directed episodes of the NBC series Homicide: Life on the Street (1998–1999), and won the Primetime Emmy Award for Exceptional Merit in Documentary Filmmaking for her work on the documentary film Cartel Land (2015). She is known for her collaborations with Eric Red and Mark Boal.

Bigelow was born in San Carlos, California, the only child of Gertrude Kathryn (née Larson; 1917–1994), a librarian, and Ronald Elliot Bigelow (1915–1992), a paint factory manager. Her mother was of Norwegian descent. She attended Sunny Hills High School in Fullerton, California.

Bigelow's early creative endeavors were as a painting student at San Francisco Art Institute, where she enrolled in the fall of 1970. While enrolled at SFAI, she was accepted into the Whitney Museum of American Art's Independent Study Program (ISP) in New York City from fall of 1971 to the spring 1972. While at the ISP, her advisers included artist Brice Marden and Susan Sontag. She received her Bachelor of Fine Arts from SFAI in December 1972. Returning to New York, for a while, Bigelow lived as an impoverished artist, staying with painter Julian Schnabel in performance artist Vito Acconci's loft. She had a minor role in Richard Serra's video Prisoner's Dilemma (1974). Bigelow teamed up with Philip Glass on a real-estate venture in which they renovated distressed apartments downtown and sold them for a profit.

Bigelow entered the graduate film program at Columbia University, where she studied theory and criticism and earned her master's degree. Her professors included Vito Acconci, Sylvère Lotringer, and Susan Sontag, as well as Andrew Sarris and Edward W. Said, and she worked with the Art & Language collective and Lawrence Weiner. While working with Art & Language Bigelow published an article, "Not on the Development of Contradiction," in the short-lived Art & Language magazine The Fox, and began a short film, The Set-Up (1978), which found favor with director Miloš Forman, then teaching at Columbia University, and which Bigelow later submitted as part of her MFA at Columbia. During her graduate studies at Columbia, she also studied under seminal film theorist Peter Wollen. Bigelow immersed herself in the critical theory that heavily influenced her first feature film. She co-directed her first film, The Loveless, with her film school classmate Monty Montgomery in 1981.

Also in 1981, she was invited by John Baldessari to teach for a single semester in the School of Art at California Institute of the Arts.

Bigelow's short The Set-Up is a 20-minute deconstruction of violence in film. The film portrays "two men fighting each other as the semioticians Sylvère Lotringer and Marshall Blonsky deconstruct the images in voice-over." Bigelow asked her actors to actually beat and bludgeon each other throughout the film's all-night shoot. Her first full-length feature was The Loveless (1981), a biker film that she co-directed with Monty Montgomery. It featured Willem Dafoe in his first starring role. Next, she directed Near Dark (1987), which she co-scripted with Eric Red. With this film, she began her lifelong fascination with manipulating movie conventions and genre. The main cast included three actors who had appeared in the film Aliens. In the same year, she directed a music video for the New Order song "Touched by the Hand of God"; the video is a spoof of glam metal imagery. Bigelow's subsequent films, Blue Steel, Point Break, and Strange Days, "merged her philosophically minded manipulation of pace with the market demands of mainstream film-making".