Behavioral parent training (BPT), behavioral classroom management, behavioral peer interventions, and multicomponent behavioral treatment interventions are effective psychosocial treatments for children with Attention-Deficit/Hyperactivity Disorder (ADHD). However, research is limited on the effectiveness of these interventions over time. The purpose of this study was to determine if a school-based behavioral health program, rooted in interventions with a strong empirical foundation, is effective in improving both short-term and long-term outcomes for students with ADHD. In addition, predictors of successful treatment outcomes were examined. Participants included 63 students who had transitioned out of the program within the past 13 to 42 months. Follow-up phone calls with parents were conducted; a parent-report questionnaire and measure of ADHD symptomatology were administered. Results indicated that students’ ADHD symptomatology improved throughout the program and gains were maintained 1 to 3.5 years later. Further, results suggested that gender and race were predictive of improvements in symptomatology during the follow-up period. Additionally, parents found the intervention program to be socially valid. Suggestions for researchers and implications for practitioners are also discussed.