Andrea Patricia Arnold OBE (born 5 April 1961) is an English filmmaker and former actress. She won an Academy Award for her short film Wasp in 2005. Her feature films include Red Road (2006), Fish Tank (2009) and American Honey (2016), all of which have won the Jury Prize at the Cannes Film Festival, while her first documentary feature Cow premiered at the 2021 Cannes Film Festival.

Arnold's television work includes directing the second season of the HBO series Big Little Lies, and four episodes each of the Amazon Prime Video series Transparent and I Love Dick.

Andrea Patricia Arnold was born on 5 April 1961 in Dartford, Kent, the eldest of four children. She was born when her mother was only 16 years old and her father was 17, and they separated when she was very young. Growing up on a council estate, she spent her youth days constantly exploring the "chalk pits, fields, woods and motorways" of Dartford. Her mother had to bring up all four children alone, which is reminiscent of the narrative in Arnold's third short film, Wasp.

As a young girl, she was writing dark stories about human experience. In an interview, Arnold speaks about how when she was 10 years old, she wrote her first play that expressed her "horror" of the slave trade, and a few years later while studying for a dance GCSE, she made a performance piece; "I took quotes from The Diary of Anne Frank and read them aloud as I moved around the room. All the other kids would just bung on some pop music and dance. I remember the examiners sitting there looking at me, perplexed." Arnold left school when she was 16, when she was drawn to becoming an actor. When Arnold was 18 years old she began working as a host and actor for a children's TV show called No. 73. She worked in TV for the next 10 years while continually writing on the side. Arnold realized she could turn her stories into films so she studied at the American Film Institute of Los Angeles, where she gained experience in the film industry. In explaining why she moved from London to study film in the U.S. she states, "I felt my lack of education and accent always held me back in the eyes of the gatekeepers".

After finishing her studies and returning to Britain she had her daughter, Coral, and began making short films for TV.

After leaving school in the late 1970s, Arnold got her first TV jobs as a dancer on shows that included Top of the Pops. She first came to prominence as an actor and television presenter alongside Sandi Toksvig, Nick Staverson and Neil Buchanan in the 1980s children's television show No. 73. This Saturday morning show on ITV, in which she played Dawn Lodge, had a similar premise to that of The Kumars at No. 42 in the way that the show was part sitcom, part chat show and based at a domestic residence. In addition to these parts, the show had the usual mix of music, competitions and cartoons that was in keeping to the formula of British Saturday morning children's TV of the 1980s. After a couple of years of experience in front of the camera, Arnold realized, "Television was great fun and I went along for the ride, but I never felt that comfortable in front of the camera".

In 1988 No. 73 had morphed into 7T3, with the set being moved from the Maidstone house (in fact in TVS studios in Kent) to that of a theme park. This revamp would only last the season, but Arnold would be seen for another two years in the same timeslot as part of the Motormouth presenting team. In 1990 she presented and wrote for the environmental awareness show for teens, A Beetle Called Derek. This also featured Benjamin Zephaniah and gave exposure to The Yes/No People of Stomp fame.

After retiring from her career as a television presenter, Arnold studied directing at the AFI Conservatory in Los Angeles and trained in screenwriting at the PAL Labs in Kent. Her early short films included Milk (1998), which premiered at the International Critics' Week Cannes, and Dog (2001). She won the Academy Award for Best Live Action Short Film for Wasp, in 2004.