Middle school special education teachers are often concerned about challenging behavior. In recent years, school wide positive behavior support (SWPBS) has been shown to be effective in improving students' behavior. Class-wide Function-related Intervention Teams (CW-FIT) is a SWPBS-based program designed to for implementation at the classroom level. CW-FIT utilizes an interdependent group contingency by utilizing social skills training, teacher praise, and positive reinforcement to improve students' behavior. Students are taught how to achieve specific social skills and then work in teams, using these social skills, to earn a group reward. CW-FIT has been effective in elementary general education classrooms. It has also worked well for small classrooms of students in elementary schools who have emotional and behavioral disorders, autism spectrum disorder, or other health impairment. CW-FIT has not yet been evaluated in a middle school special education setting. The present study examined the effects of CW-FIT implementation on teacher praise rates and student on-task behavior in a middle school self-contained classroom, where 12 of the students had severe disabilities and 11 were typically-developing peer tutors. A single-subject, reversal design was used to evaluate impact. Results indicate that CW-FIT increased teacher praise rates and student on-task behavior. Both teachers and students reported CW-FIT to be socially valid. The present study suggests promising results for the implementation of CW-FIT in a middle school self-contained classroom. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]