O’Casey’s three most famous plays, those of his ‘Dublin Trilogy’, were subtitled as tragedies, yet the playwright had little time for academic theorizing and at one stage declared Aristotle was ‘all balls’. Early critics tended to set aside O’Casey’s definitions of his three famous plays as tragedy, preferring terms such as ‘tragi-comedy’, and, aside from Rónán McDonald, most later critics have ignored the issue. This chapter does not start from a specific formal model of tragedy, but instead examines The Shadow of a Gunman, Juno and the Paycock, and The Plough and the Stars to see how the audience or reader’s experience of these plays might relate to tragedy.