William John Banville (born 8 December 1945) is an Irish novelist, short story writer, adapter of dramas and screenwriter. Though he has been described as "the heir to Proust, via Nabokov", Banville himself maintains that W. B. Yeats and Henry James are the two real influences on his work.

Banville's work has led to many accolades, including the 1976 James Tait Black Memorial Prize, the 2005 Booker Prize, the 2011 Franz Kafka Prize, the 2013 Austrian State Prize for European Literature and the 2014 Prince of Asturias Award for Literature. Elected a Fellow of the Royal Society of Literature in 2007, Italy made him a Cavaliere of the Ordine della Stella d'Italia (essentially a knighthood) in 2017. He is a former member of Aosdána, having voluntarily relinquished the financial stipend in 2001 to another, more impoverished, writer.

Born at Wexford in south-east Ireland, Banville published his first novel, Nightspawn, in 1971. A second, Birchwood, followed two years later. "The Revolutions Trilogy", published between 1976 and 1982, comprises three works, all of which reference renowned scientists in their titles: Doctor Copernicus, Kepler and The Newton Letter. His next work, Mefisto, had a mathematical theme. His 1989 novel The Book of Evidence, shortlisted for the Booker Prize and winner of that year's Guinness Peat Aviation award, heralded a second trilogy, three works which deal in common with the work of art. "The Frames Trilogy" is completed by Ghosts and Athena, both published during the 1990s. Banville's thirteenth novel, The Sea, won the Booker Prize in 2005. In addition, he publishes crime novels as Benjamin Black — most of these feature the character of Quirke, an Irish pathologist based in Dublin.

Banville is considered a contender for the Nobel Prize in Literature. He lives in Dublin.