Around the world, 473 million children live in unstable and conflict-affected environments. Children who witness or are victims of violence during the most formative years of development are particularly vulnerable to lasting mental health and psychosocial problems. Yet less than 1% of development aid is allocated to mental health services. Many children affected by conflict do not have access to mental health and psychosocial support (MHPSS) interventions. There are interventions that work, but they fail to be applied on a large scale. Moreover, humanitarian, development and peace efforts are not connected. The article focuses on integrating child mental health responses into recovery, development and peacebuilding in these settings.