Multisystemic Therapy (MST) is an evidence-based intervention for youth at risk of severe system consequences due to serious externalizing, anti-social, and/or delinquent behaviors (e.g., criminal activity, substance use) and their families. Youth and families receive treatment within the systems they are embedded in, such as their homes, schools, and communities, via licensed Multisystemic Therapy providers, which consist of a team (or teams) of 2-4 therapists and a supervisor. MST teams are on call 24/7 to provide treatment when and where it is needed—within any combination of these systems—and are dedicated to improving youth and family functioning.