Background: Estimates of the number of children affected by mental disorders and the percent of them receiving treatment interventions are essential to guide planning for public mental health services.Methods: We interpret findings from our recent systematic review and meta-analysis on the prevalence and impact of childhood mental disorders.Results: We identified 14 high-quality epidemiological studies meeting all of our inclusion criteria, including representative sampling and use of rigorous diagnostic measures. This resulted in the inclusion of nearly 62,000 children aged four to 18 years from 11 high-income countries. Our meta-analysis found that 12.7% of children met diagnostic criteria for a mental disorder at any given time. Additionally, our analysis found that among children with mental disorders, only 44.2% received any services for these conditions.Conclusions: Data show that there are serious mental health service shortfalls which represent a violation of children's rights and prevent children from flourishing. We present a population health strategy to help address these deficits.