Research was limited when it came to the roles and responsibilities of middle school assistant principals. Even less research was dedicated to how middle school teachers perceived the roles and responsibilities of their assistant principals. Due to the overall lack of research regarding both facets, further research was necessary to form a better understanding of middle school assistant principals' roles and responsibilities as compared to teachers' perceptions. Middle school assistant principals and teachers from one Tennessee county responded to questionnaires to explore the relationship between middle school assistant principals' perceptions of their roles and responsibilities and the teachers' perceptions of assistant principals' roles and responsibilities. Three themes formed assistant principals' self-perception: "students, teachers, and managerial duties and tasks." Additionally, three themes formed teachers' perceptions of the roles and responsibilities of assistant principals: "student discipline and behavioral management, teacher support, overall school management." This study was foundational study as it could be used as the framework for future studies exploring middle school assistant principals' roles and responsibilities. [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://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]