Sebastian Barry (born 1955) is an Irish novelist, playwright and poet. He was named Laureate for Irish Fiction, 2018–2021. He was named a Chevalier des Arts et des Lettres by the French government in 2024.

Barry has been twice shortlisted for the Man Booker Prize for his novels A Long Long Way (2005) and The Secret Scripture (2008), the latter of which won the 2008 Costa Book of the Year and the James Tait Black Memorial Prize. His 2011 novel, On Canaan's Side, was longlisted for the Booker. In January 2017, Barry was awarded the Costa Book of the Year prize for Days Without End, becoming the first novelist to win the prestigious prize twice.

Barry was born in Dublin. His mother was acclaimed actress Joan O'Hara. One of Barry's grandfathers belonged to the British Army Corps of Royal Engineers. His other grandfather was a painter, a Nationalist, and a devotee of De Valera.^{[citation needed]}

He was educated at Catholic University School and Trinity College Dublin, where he read English and Latin.

Barry's academic posts have included Honorary Fellow in Writing at the University of Iowa (1984), Heimbold Visiting Professor at Villanova University (2006) and Writer Fellow at Trinity College, Dublin (1995–1996).

Barry's first literary publication was the novel Macker's Garden in 1982. His first play, The Pentagonal Dream, starred Olwen Fouéré and debuted in the Damer Theatre in March 1986. This was followed by several books of poetry and a further novel, The Engine of Owl-Light in 1987, before his career as a playwright began with his first play produced in the Abbey Theatre, Boss Grady's Boys, in 1988.

Barry's maternal great-grandfather, James Dunne, provided the inspiration for the main character in his most internationally known play, The Steward of Christendom (1995), which won the Christopher Ewart-Biggs Memorial Prize, the Lloyd's Private Banking Playwright of the Year Award and other awards. The main character, named Thomas Dunne in the play, was the chief superintendent of the Dublin Metropolitan Police from 1913 to 1922. He oversaw the area surrounding Dublin Castle until the Irish Free State takeover on 16 January 1922.

Both The Steward of Christendom and the novel The Whereabouts of Eneas McNulty (1998) are about the dislocations (physical and otherwise) of loyalist Irish people during the political upheavals of the early 20th century. The title character of the latter work is a young man forced to leave Ireland by his former friends in the aftermath of the Anglo-Irish War.^{[citation needed]}