Project Summary Abstract Suicide is a leading cause of death in youth across the United States. Approximately 80% of youth who die by suicide interface with the medical system in the year preceding their death. Primary care practices (PCPs) serving youth are well positioned to detect patients at risk for suicide and intervene, and widely accessible toolkits are available for practices to use. However, effective ways to impact providers’ skills in actually implementing a clinical pathway to manage at-risk patients remain underexplored. Indeed, training without applied practice and support is likely insufficient to significantly impact these skills in the long term and less likely to improve patient outcomes. Practice facilitation is a powerful way to transform clinical practice, develop provider skills, and improve patient outcomes. Our team trains PCPs in the NIMH youth suicide prevention care pathway and, in addition, assists them in integrating the pathway into routine care with longitudinally with feedback, implementation support through practice facilitation and data collection. However, there is limited evidence for the effects of supplemental supports, such as practice facilitation or coaching, on primary care providers’ adoption of and competence in suicide risk assessment and management. Thus, guided by the combined Reach, Effectiveness, Adoption, Implementation, Maintenance (RE-AIM)/Practical Robust Implementation and Sustainability (PRISM) framework, this cluster-randomized trial will compare the impact of practice facilitation added to didactic suicide prevention training based on the NIMH youth suicide prevention care pathway (TO+PF) versus training only (TO). In this pilot type 3 hybrid effectiveness- implementation trial, Pediatric and Family Medicine practices in our practice-based research networks will be randomized to TO+PF or to TO. Providers in clinics randomized to the TO+PF arm will also receive practice facilitation for 6 months, involving mo