SUMMARY Adolescents are at increasing risk of overdose death. Since 2020, the overdose crisis has expanded most rapidly among younger populations, largely because of the recent reality that any illicit substance (e.g., counterfeit pharmaceuticals, methamphetamines) used by adolescents has the potential to contain lethal amounts of fentanyl. Preventing overdose deaths will require identifying and treating youth with any substance use disorder (SUD) or occasional opioid use – including but not limited to opioid use disorder (OUD) – due to potential fentanyl contamination. Access to experienced, qualified SUD/OUD treatment providers for adolescents is far below what is needed, with an even greater disparity noted than for adults needing treatment. Adding specialists to the workforce will help, but the urgency of the national overdose crisis requires innovative changes to current adolescent SUD/OUD care models to improve availability of effective assessment and treatment services. Primary Care Providers (PCPs) could fill a portion of the gap of the behavioral health workforce, but they often lack formal SUD training and resources and feel unqualified to diagnose and treat SUDs, particularly in youth. Integrated care models, where PCPs work closely with behavioral health specialists to deliver appropriate care to patients with SUD/OUD, are a promising but understudied approach in pediatric contexts. Therefore, with input from national experts and local stakeholders, the research team will conduct a Hybrid Type 2 effectiveness- implementation, cluster-randomized trial to study a multifaceted intervention to change the procedural and cultural norms of pediatric primary settings. This project capitalizes on the infrastructure established through a large-scale roll out of integrated behavioral health (IBH) in a statewide health system. Intervention components for this adolescent SUD IBH include task-shifting within primary care to facilitate delivery of brief SUD interventions, case management, electronic decision support tools, and stigma-reduction interventions. The primary purpose of the proposed intervention is to formally combine and build on the resources available through these interventions to shift primary care practice toward delivering effective adolescent SUD care and, ultimately, to prevent overdose deaths among adolescents.