This study examined perceptions of teachers who implemented a tiered system of support, the comprehensive, integrated, three-tiered (Ci3T) model of prevention. We reported findings of four focus groups with a total of 18 elementary teachers who implemented Ci3T for 2 years. While the Ci3T model comprised elements addressing academics, behavior, and social-emotional learning, teachers were predominately concerned with issues related to students' behavior. Teachers reported difficulty moving from reactive to proactive classroom management approaches theoretically grounded in behavioral principles.