Sarah Ann Waters OBE (born 21 July 1966) is a Welsh novelist. She is best known for her novels set in Victorian society and featuring lesbian protagonists, such as Tipping the Velvet and Fingersmith.

Sarah Waters was born in Neyland, Pembrokeshire, Wales, in 1966. She later moved to Middlesbrough, England, when she was eight years old. She grew up in a family that included her father Ron, mother Mary, and a "much older" sister. Her mother was a housewife and her father an engineer who worked on oil refineries. She describes her family as "pretty idyllic, very safe and nurturing". Her father, "a fantastically creative person", encouraged her to build and invent.

Waters said, "When I picture myself as a child, I see myself constructing something, out of plasticine or papier-mâché or Meccano; I used to enjoy writing poems and stories, too." She wrote stories and poems that she describes as "dreadful gothic pastiches", but had not planned her career. Despite her obvious enjoyment of writing, she did not feel any special calling or preference for becoming a novelist in her youth.

I don’t know if I thought about it much, really. I know that, for a long time, I wanted to be an archaeologist – like lots of kids. And I think I knew I was headed for university, even though no one else in my family had been. I really enjoyed learning. I remember my mother telling me that I might one day go to university and write a thesis, and explaining what a thesis was; and it seemed a very exciting prospect. I was clearly a bit of a nerd.

Waters was a supporter of the Campaign for Nuclear Disarmament, joining as a result of her boyfriend at the time. Politically, she has always identified as a leftist.

After Milford Haven Grammar School, Waters attended university and earned degrees in English literature. She received a BA from the University of Kent, an MA from Lancaster University, and a PhD from Queen Mary, University of London. Her PhD thesis, entitled Wolfskins and togas: lesbian and gay historical fictions, 1870 to the present, served as inspiration and material for future books. As part of her research she read 19th-century pornography, in which she came across the title of her first book, Tipping the Velvet. However, her literary influences are also found in the popular classics of Victorian literature, such as Charles Dickens, Wilkie Collins, Mary Shelley and the Brontës, and in the contemporary novelists that combine a keen interest in Victoriana with a post-modernist approach to fiction, especially A.S. Byatt and John Fowles. Angela Carter's Nights at the Circus had a huge influence on her début novel as well; Waters praises Carter for her literary prose, her "common touch", and her commitment to feminism.

Waters came out as lesbian in the late 1980s. She has been in a relationship with copy editor Lucy Vaughan since 2002. As of 2007, she lived in Kennington, south-east London.

Before writing novels, Waters worked as an academic, earning a doctorate and teaching. Waters went directly from her doctoral thesis to her first novel. It was during the process of writing her thesis that she thought she would write a novel; she began as soon as the thesis was complete. Her work is very research-intensive, which is an aspect she enjoys. Waters was briefly a member of the long-running London North Writers circle, whose members have included the novelists Charles Palliser and Neil Blackmore, among others.