This article considers the implications of theory and research in developmental psychopathology for existing and emerging social policy concerning treatment of child and adolescent psychopathology. Based on the concept that all psychopathology is a process, four core principles of a developmental psychopathology perspective are discussed. In turn, each is applied to an evaluation of policy issues with implications for intervention, including mental health parity, treatment guidelines, mental health reimbursement, and level of intervention. It is concluded that social policy on treatment must be based on an empirically supported theory of developmental psychopathology and on evidence-based interventions that link treatments to pathogenic processes.