Voluntary sector organisations (VSOs) play a pivotal, but as yet unevaluated role in the Irish criminal justice system. The aim of this paper is to address some of the key issues and debates discussed in the extensive international literature on the criminal justice voluntary sector and to consider how they might be translated into an Irish context. After presenting the contours of the Irish criminal justice voluntary sector and discussing the difficulties of scoping a complex and diverse field, the paper highlights key strengths and weaknesses discussed in the international literature. The Irish criminal justice voluntary sector ultimately has to be interpreted as an element of broader Irish penal and social policy. Making it visible as a distinct field of intervention and research is important if we want to highlight some of the sector’s undeniable strengths. However, it is also timely to critically interrogate some of its tensions and contradictions in a way that will ultimately be useful to service users, practitioners and policy-makers alike.