Classroom management is a common concern for teachers. Music teachers in particular experience unique behavior challenges because of large class sizes, uncommon pacing requirements, and performance-based outcomes. Positive behavior support (PBS) is an evidence-based framework for preventing or eliminating challenging behaviors by teaching and reinforcing appropriate social skills. Class-Wide Function-Related Intervention Teams (CW-FIT), a specific PBS intervention involving social skills instruction, positive reinforcement, and group contingencies, has proven effective in elementary schools but has not been evaluated specifically in music classrooms. The present study sought to investigate the effectiveness of CW-FIT in increasing on-task behavior and teacher praise-to-reprimand ratios in a sixth-grade music classroom. A single-subject reversal (ABAB) design was used. Results indicated that student on-task behavior increased when CW-FIT was implemented. Teacher praise-to-reprimand ratios also improved. Results suggest the teacher and the students found CW-FIT valuable and enjoyable. Study limitations and implications are addressed. [This paper was published in "Update: Applications of Research in Music Education" v35 n3 p23-30 Jun 2017 (EJ1140013).]