BACKGROUND: Globally, mental disorders are the leading cause of disability among children and adolescents. To date, there has been no estimate of developmental assistance supporting mental health projects that target children and adolescents (DAMH-CA). This study aimed to identify, describe and analyse DAMH-CA with respect to annual trends (2007-2014), sector, project type, recipient regions, and top donor and recipient countries, and estimate annual DAMH-CA per child/adolescent by region. METHODS: Developmental assistance for all projects focused on children and adolescent mental health between 2007 and 2014 was identified on the Organisation for Economic Co-operation and Development's (OECD) Creditor Reporting System, and analysed by target population, sector, project type, donors, and recipients. The study did not include governmental or private organisation funds, nor funding for projects that targeted the community or those that included mental health but not as a primary objective. RESULTS: Between 2007 and 2014, 704 projects were identified, constituting US$ 88.35 million in DAMH-CA, with an average of 16.9% of annual development assistance for mental health. Three quarters of DAMH-CA was used to fund projects in the humanitarian sector, while less than 10% was directed at mental health projects within the education, HIV/AIDS, rights, and neurology sectors. DAMH-CA was predominantly invested in psychosocial support projects (US$ 63.24 million, 72%), while little in absolute and relative terms supported capacity building, prevention, promotion or research, with the latter receiving just US$ 1.2 million over the eight years (1.4% of total DAMH-CA). For 2014, DAMH-CA per child/adolescent was US$ 0.02 in Europe, less than US$ 0.01 in Asia, Africa, and Latin America and the Caribbean, and US$ 0 in Oceania. CONCLUSIONS: To mitigate the growing burden of mental and neurological disorders, increased financial aid must be invested in child and adolescent mental health, especially with respect to capacity building, research and prevention of mental disorder projects. The present findings can be used to inform policy development and guide resource allocation, as current developmental assistance is described by sector and project type, thereby facilitating the identification of specific areas of investment need.