For decades, empirically tested youth interventions have prevented dysfunction by addressing risk and ameliorated dysfunction through treatment. The authors propose linking prevention and treatment within an integrated model. The model suggests a research agenda: Identify effective programs for a broadened array of problems and disorders, examine ethnicity and culture in relation to intervention adoption and impact, clarify conditions under which programs do and do not work, identify change mechanisms that account for effects, test interventions in real-world contexts, and make tested interventions accessible and effective in community and practice settings. Connecting the science and practice of prevention and treatment will be good for science, for practice, and for children, adolescents, and their families.