Youth substance use is associated with increased risk for delinquency; academic underachievement; teen pregnancy; sexually transmitted infections; perpetration of, or experience with, violence; injuries; and mental health problems. Youth, parents, and families are key sectors involved in the Drug-Free Communities (DFC) Support Program, the nation’s leading effort to mobilize communities to prevent youth substance use. Preventing or delaying substance use initiation among youth reduces later risk for substance use, substance use disorders, and overdose. The need for prevention is vital and early intervention is critical for youth.