The police reform process in Northern Ireland is one of the most high-profile examples of institutional change in policing in recent years (Mulcahy 2006; Murphy 2013), and has been accorded the status of a ‘model’ for police reform generally (Ellison 2007). Analysis of any particular context must be attentive to the specificity of the issues involved, but equally it should seek to highlight developments that have a general relevance. In Northern Ireland's case, police reform was recognised as a central component of the peace process through the establishment of the Independent Commission on Policing (ICP) in Northern Ireland (the Patten Commission). The ICP specified new arrangements that could command widespread and cross-community support, and its reform programme laid the basis for an extensive transformation of policing. In this chapter I consider the reform programme outlined by the Patten Commission and assess its impact on policing in Northern Ireland. I also reflect on the wider relevance of these developments and the lessons they offer for police reform efforts elsewhere. I begin by considering the context from which the Patten Commission emerged.