Assistant principals are essential to the campus leadership team as instructional leaders. However, many assistant principals spend most of their day participating in noninstructional leadership duties and responsibilities. This can drastically reduce the assistant principal's ability to fulfill instructional leadership duties, thus negatively impacting the school's vision and goals. This study explores middle school assistant principals' perceptions about their development and support as instructional leaders and how middle school campus principals support the development of assistant principals as instructional leaders in North Texas public schools. The researcher utilized a convenience sampling based on the school district and campus level where they work. The participants include one middle school assistant principal from each of the three middle schools and their campus principal in the same school district. The researcher used semi-structured interviews among three middle school assistant principals and each of their campus principals and participant observations of each middle school assistant principal. Deductive and inductive coding and analysis were used to analyze the semi-structured interviews and participant observations. Using Kaplan and Owings' (1999) and Zahn et al.'s (2020) work on the shared instructional leadership framework: vision co-designer, teacher coach and evaluator, master schedule designer, program developer, instructional manager, and communicator. Five of the six roles were identified during the coding and data analysis, including three other themes: inhibitors, assistant principal role preparation for principalship, and the principal's role in developing the assistant principal as an instructional leader. The author holds that the study's findings may still be applied to similar contexts and add to the current literature about assistant principals and their development as instructional leaders. [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.]