This chapter reflects on Sean O’Casey’s work from a postcolonial critical perspective. The focus is firstly upon his early Abbey plays, especially The Plough and the Stars, which are shown to be significant for postcolonial criticism because of their content, the contexts of their initial Abbey productions, and the ways that key aspects of their critical history play outsized roles in framing understandings of the postcolonial critical endeavour. The chapter shows how O’Casey responded to the political complexities of Ireland’s revolutionary era of the 1910s and 1920s. The chapter then examines O’Casey’s later plays, showing how his responses to the revolutionary era evolved as he dealt directly with postcolonial Ireland and the fascism of the 1930s–1960s.