Mark O'Halloran (Irish: Marcas Ó hAllmhuráin) is an Irish scriptwriter and actor. He is a native of Ennis, County Clare. He has written award-winning[1][2] screenplays for the films Adam & Paul (in which he co-starred) and Garage and the RTÉ mini-series Prosperity. In 2019 he starred with Stephen Graham in the Channel 4 miniseries The Virtues, written and directed by Shane Meadows.