Substance use and substance use disorders can harm children, youth, and families in myriad ways, including through prenatal exposure, child welfare involvement, child and youth development, and juvenile justice involvement. Child Trends’ analyses point to persistent inequities by race and ethnicity in access to effective substance use prevention and treatment. Our work informs schools, districts, states, juvenile justice systems, policymakers, and clinicians on preventing substance use, expanding access to treatment, understanding treatment outcomes, and preventing negative outcomes. Our researchers also analyze policies related to the opioid epidemic to highlight promising strategies for policymakers to determine how to prevent and treat substance use disorders and prevent overdoses among youth and their families.