Peacekeeping mitigates killing, but nonlethal violence also influences both positive peace and stability. We evaluate peacekeepers’ effect on one such type of abuse, sexual violence. We posit that peacekeepers raise the cost of abuses and foster institutional and cultural changes that curb violence. We find that missions both reduce the chance of any violence and limit its prevalence; larger deployments and multidimensional missions are more effective. Governments curtail violence more quickly than rebels do in response to military contingents; rebels are especially responsive when missions include large civilian components. These findings contribute to our understanding of peacekeeping in three primary ways: we expand the evaluation of peacekeeping to consider nonlethal violence; we draw attention to mission size, capacity to use force, and civilian-led programming as determinants of effectiveness; and we demonstrate how addressing nonlethal violence requires similar tools as lethal violence but is further enhanced by specific civilian-led initiatives.