The promotion of appropriate behavior in children with behavior disorders is one of the most arduous and time-consuming tasks faced by classroom teachers and parents. To support appropriate behavior across multiple settings, professionals need to have access to effective assessment and intervention strategies. In addition, there must be an understanding of school and family characteristics that may be contributing to or sustaining problematic behavior. Accordingly, this issue focuses on the development, assessment, and treatment of children that exhibit disruptive behavior in classrooms, at play, and home. Authors address a diverse representation of assessment and intervention strategies, illuminate the scope of current research agendas, and much more.