The aim of this article is to examine the impact of the Conflict on the development and character of the prison system in Northern Ireland. It traces the use of imprisonment to repress challenges to the legitimacy of the state, and the ways in which prisoners and communities have resisted oppressive penal policies. Evidence is presented that notwithstanding the peace process and early release of most politically-motivated prisoners, regimes within the North's three prison establishments remain heavily influenced by the experience of violence, with a prioritization of security over care and rehabilitation. The establishment, in 2010, of an independent Prison Review led by Dame Anne Owers, has presented an opportunity to address the underlying problems within the prison system. The article concludes by exploring the implications of the Northern Ireland experience for other transitional jurisdictions undergoing penal reform. Abstract published by arrangement with John Wiley & Sons.