The experience of child soldiers during postwar civilian reintegration is recognized as a major contributor to mental health. For some children, postwar social relations may be more important than war trauma in determining psychosocial well-being. Mixed methods incorporating epidemiology and qualitative case studies were employed to evaluate the effects of family, peer, and community relations after reintegration on psychosocial outcomes: hope, functional impairment, and post-traumatic stress disorder (PTSD). Participants were 142 child soldiers, including 9 qualitative case studies. Peer support predicted increased hope, decreased functional impairment, and decreased PTSD symptoms. Conversely, problems with peer relations predicted less hope and more PTSD symptoms. Maximizing peer support and minimizing stigma from peers should be prioritized within psychosocial reintegration programs, especially among former child soldiers with PTSD.