Prisoners and ex-prisoners have played a prominent role in modern Irish history. Yet despite using their prison experience for political advancement, on release, few political leaders became vocal advocates of penal reform in general or prisoner enfranchisement in particular. Prior to the passing of the Electoral (Amendment) Act in 2006, Irish prisoners were in an anomalous position: they were allowed to register, but no facility existed, for them to vote. However, this did not prevent prisoners from engaging with, and at times, challenging the political system, both north and south throughout the 20th century. Much has been written about political activity among prisoners in Northern Ireland but relatively little about their endeavors in the Irish Republic. This article begins with an examination of political participation among prisoners in the early decades of the Irish State. Despite the legal and political struggle by prisoners and penal reformers to achieve enfranchisement, when it was granted, it was in the context of electoral, rather than penal reform. Prisoner enfranchisement did not become a major issue in Ireland in contrast to other countries and reasons are examined from a historical and political perspective.