Gabriel James Byrne (Irish: Gabriel Séamas Ó Broin; born May 12, 1950) is an Irish actor, film director, film producer, and writer, as well as an audiobook narrator. His acting career began in the Focus Theatre before he joined London’s Royal Court Theatre in 1979. Byrne's screen début came in the Irish soap opera The Riordans and the spin-off show Bracken. The actor has now starred in over 35 feature films, such as The Usual Suspects, Miller's Crossing and Stigmata, in addition to writing two. Byrne's producing credits include the Academy Award-nominated In the Name of the Father. Currently, he is receiving much critical acclaim for his role as Dr. Paul Weston in the HBO drama In Treatment.

Byrne, the first of six children, was born in Dublin, Ireland, the son of a cooper and soldier, Dan, and a hospital nurse from Galway, Eileen (née Gannon). His siblings are Donal, Thomas, Breda, Margaret, and Marian, who died at a young age. Byrne was raised Catholic and educated by the Irish Christian Brothers. Despite spending five years of his childhood in a seminary training to be a priest, he said in an interview, "I spent five years in the seminary and I suppose it was assumed that you had a vocation. I have realised subsequently that I didn't have one at all." He attended University College Dublin, where he studied archaeology and linguistics, becoming proficient in Irish. He played football in Dublin with the famous Stella Maris Football Club in Drumcondra.

Byrne worked in archaeology when he left UCD but maintained his love of his language, writing the first drama in Irish, Draíocht, on Ireland's national Irish language television station, TG4, when it began broadcasting in 1996.