This article examines the effectiveness of an evidence-based behavioral treatment package for children with inattentive and disruptive behavior problems when delivered in the context of a school-based mental health program. Child symptomatology and functioning are assessed in a treatment group (n = 30) and a waitlist control group (n = 12) across multiple time points (fall, winter, and spring). Treatment includes a daily report card procedure, year-long teacher consultation, and parenting sessions. According to the parent report, treated children show marked reductions in hyperactive and impulsive, oppositional or defiant and aggressive behavior, and marked improvement in peer relationships. Teachers observe treatment-related group differences in inattention, academic functioning, and the student-teacher relationship. Feasibility and acceptability data have implications for transporting evidence-based treatments to community settings and for integrating mental health services into the culture of the school community. (Contains 6 tables and 3 figures.)