Are UN peacekeepers effective in protecting civilians from violence? Existing studies examine this issue at the country level, thereby making it difficult to isolate the effect of peacekeepers and to assess the actual mechanism at work. We provide the first comprehensive evaluation of UN peacekeeping success in protecting civilians at the subnational level. We argue that peacekeepers through their sizable local presence can increase the political and military costs for warring actors to engage in civilian targeting. Since peacekeepers’ access to civilian populations rests on government consent, peacekeepers will primarily be effective in imposing these costs on rebel groups, but less so for government actors. To test these conjectures we combine new monthly data on the location of peacekeepers with data on the location and timing of civilian killings in Africa. Our findings suggest that local peacekeeping presence enhances the effectiveness of civilian protection against rebel abuse, but that UN peacekeeping struggles to protect civilians from government forces.