Communal violence remains an enduring experience across many multi-ethnic societies, affecting daily activities and providing the opportunity for conflict escalation by unconstrained citizens and elites. Previous research and practice on addressing these challenges have been largely motivated by two main theories: 1) bottom-up theories that aim to build social cohesion between groups and changing norms, and 2) top-down theories that seek to quell violence and reduce the cost of conflict. Yet, there is still mixed evidence on the mechanisms underpinning these theories as well as the extent to which they may complement each other. In 88 communities across three states in Nigeria, we examine the effects of mediation training (top-down) and community dialogues (bottom-up) on violence, insecurity, and trust in a large-scale randomized control trial. The results will provide insight into how these types of interventions can support peace where state presence is weak.