Individuals with ADHD symptoms are at an increased risk of lifetime trauma exposure. However, research has yet to fully examine whether symptoms of ADHD function as a temporal risk factor for experiencing trauma and specific mechanisms that may explain the association between symptoms of ADHD and trauma exposure. Two constructs that may account for the relation between ADHD symptoms and trauma are deviant peer association and neighborhood disadvantage. The present study sought to 1) elucidate the temporal nature of ADHD symptoms and exposure to trauma and 2) examine whether peer deviancy and/or neighborhood disadvantage mediate the relation between childhood ADHD symptoms and subsequent trauma exposure across a 20-year longitudinal cohort study. Participants (N = 616) were predominantly Black/African American (86%; Male n = 389) from an urban school district. Using structural equation modeling, total trauma exposures during young adulthood (Years 17-20) were regressed on parent- and teacher-rated ADHD symptoms in Grade 1 (Year 1). A significant indirect path from ADHD symptoms to trauma exposure through deviant peer affiliation (Year 16) indicated that having childhood ADHD symptoms predicted deviant peer affiliation 16years later, which in turn predicted greater exposures to traumatic events during young adulthood, controlling for neighborhood disadvantage. Neighborhood disadvantage was not a significant mediator when accounting for peer deviancy. Taken together, findings contribute to a limited body of research that utilizes a prospective design to examine the association between childhood ADHD symptoms and trauma exposure in young adulthood among Black/African American youth. Potential targets for intervention are proposed.