Across the United States performance expectations of principal supervisors are shifting from a focus on compliance to a focus on instructional leadership development. The problem addressed in this study was that principal supervisors were applying feedback and coaching approaches inconsistently as they addressed school principals' growth as instructional leaders. The conceptual framework was transformational leadership, through which leaders encourage, inspire, and motivate employees to innovate and create change that can help grow and shape future academic success for the students they serve. The research questions were designed to explore how principal supervisors provide feedback and coaching to develop school principals' instructional leadership practices. Data were collected through semistructured interviews with eight supervisors from one mid-Atlantic school district. A combination of a priori and open coding was used within thematic analysis. Distilled themes included effective instructional leadership, feedback practices, coaching practices, and the evaluation process. The principal supervisors agreed on the importance of site-based leadership and collaboration and used varied ways of giving feedback and providing coaching; however, it was unclear how they customized these efforts to meet the needs of individual principals. Implications and recommendations include using data to support evaluation of principals, principal supervisors, and the supervisors of all school personnel--with the primary goal being the improvement of instructional practices for student success. Creating and expanding focused and collaborative feedback and coaching cultures within school systems can support enhanced instruction and positive social change for all learners within the schools. [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.]