Highlights• Community violence witnessing and victimization are associated with externalizing behaviors.• Armed conflict exposure is associated with externalizing behaviors and developmental competence.• School safety, connectedness, and services moderate relation between witnessing and externalizing.• School services moderates relation between victimization and competence.• School climate has implications for mitigating the effects of violence exposure for adolescents.Abstract In Colombia, many adolescents have experienced violence related to the decades-long armed conflict in the country and have witnessed or been directly victimized by violence in their communities, often related to gang activity or drug trafficking. Exposure to violence, both political and community violence, has detrimental implications for adolescent development. This study used data from 1857 Colombian adolescents in an urban setting. We aim to understand the relations between exposure to violence and adolescent outcomes, both externalizing behaviors and developmental competence, and then to understand whether school climate (i.e., safety, connectedness, services) moderates these relations. Results demonstrate that armed conflict, community violence victimization, and witnessing community violence are positively associated with externalizing behaviors, but only armed conflict is negatively associated with developmental competence. School safety, connectedness, and services moderate the relation between community violence witnessing and externalizing behaviors. School services moderates the relation between community violence victimization and developmental competence. As students perceived more positive school climate, the effects of community violence exposure on outcomes were weakened. This study identifies potential levers for intervention regarding how schools can better support violence-affected youth through enhancements to school safety, connectedness, and services.