PROJECT SUMMARY/ABSTRACT While post-concussive symptoms following sports-related concussion are typically transient and resolve spontaneously within two weeks of concussive injury, 14% or more of youth who sustain concussion experience significant morbidity that can persist well beyond the normal disease course. Furthermore, post- concussive symptoms commonly co-occur with affective symptoms including depression and anxiety which when present can prolong recovery from primary post-concussive symptoms. Together, persistent physical and psychological symptoms confer protracted functional impairment and create a significant burden for affected youth, their family, and school. Currently, there are no evidence-based guidelines to inform treatment of persistent post-concussive symptoms in youth and adolescents. In response to the dearth of evidence-based treatment approaches for youth with persistent post- concussive symptoms, we developed a novel collaborative care treatment model that simultaneously targets post-concussive symptoms and co-occurring depression and anxiety. Athletes and their family members receive patient navigator care management services that bridge post-injury care across acute care, specialist and primary care health service delivery sectors, in addition to cognitive behavioral psychotherapy. Patients who remain symptomatic after initial treatment efforts receive stepped-up care that may include psychopharmacologic consultation. We will conduct a randomized comparative effectiveness trial with 200 youth, ages 11-18, suffering from ≥ 3 post-concussive symptoms at least 1 month after their sports-related injury. Athletes will be randomized to collaborative care (intervention) or post-sports injury care as usual (control group) conditions. We will determine the effectiveness of a stepped-collaborative care intervention model in reducing post-concussive and co-occurring psychological symptoms in youth with persistent post- concussive symptoms after sports-related concussion; examine the effectiveness of the intervention in improving function and health-related quality of life amongst youth with persistent symptoms after sports- related concussion; and explore differences in school performance between groups.