Efforts to implement R2P in practice have consistently pointed to peace operations as one possible avenue. For example, the Secretary-General has identified United Nations (UN) peacekeeping missions as an appropriate instrument for operationalizing R2P. The emergence of the Protection of Civilians (POC) as a center of gravity for modern UN peacekeeping has led many to identify synergies and adds further weight to the case. However, implementing R2P through UN peacekeeping presents a number of principled, political, and practical challenges. This chapter explores these issues. The first section traces the broadening and deepening of POC in recent years and analyzes its significance for implementing R2P, as well as for the current consensus on UN peacekeeping. The second section draws on empirical examples from the field, including the POC sites in South Sudan and the Force Intervention Brigade in the Democratic Republic of the Congo, to identify a range of opportunities as well as challenges associated with emergent POC strategies and practices in the field. The final section lays out a series of recommendations highlighting where more work is required to enhance the implementation of R2P through the UN’s peace operations going forward.