Gabriel James Byrne (born 12 May 1950) is an Irish actor. He has received a Golden Globe Award and nominations for a Grammy Award, two Primetime Emmy Awards and two Tony Awards. Byrne was awarded the Irish Film and Television Academy Lifetime Achievement Award in 2018 and was listed at number 17 on The Irish Times list of Ireland's greatest film actors in 2020. In 2009, The Guardian named him one of the best actors who never received an Academy Award nomination.

Byrne's acting career began at the Focus Theatre in Dublin before he joined London's Royal Court Theatre in 1974. His screen debut came in the Irish drama serial The Riordans and the spin-off show Bracken. He went on to star in such films as Defence of the Realm (1986), Lionheart (1987), Miller's Crossing (1990), Little Women (1994), Dead Man (1995), The Usual Suspects (1995), The Man in the Iron Mask (1998), Enemy of the State (1998), Vanity Fair (2004), The 33 (2015), and Hereditary (2018). He co-wrote The Last of the High Kings (1996) and produced In the Name of the Father (1993).