This program evaluation focused on mid-range outcomes of a leadership academy for school principals. The mixed-methods evaluation included interviews, principals' instructional observation database, and teacher surveys. The Principal Academy program was designed to build principals' knowledge of high-yield instructional strategies (Hattie, 2009), expertise with tools to collect classroom data that provide immediate feedback to teachers, and facilitate collaborative observation conferences to engage teachers in professional learning to improve classroom instructional practices. Participants in the study included Academy leaders and directors, principals, and identified teachers. Interviews revealed evidence of principals' increased knowledge of intended instructional strategies and targeted professional learning for teachers associated with the instructional strategies. During the Academy, principals' accuracy and rate of instructional observations increased. Teachers reporting higher frequency of instructional interactions with principals also reported higher degrees of instructional change. A positive correlation was found between teachers' perceptions of principal support and instructional change, and perceptions of principal support related to instruction were higher with increased frequency of principal interactions. Teachers also reported that principal feedback, supportive behaviors, modeling, and engagement had a positive impact on their instruction. Implications for practice include ensuring that principals have access to high quality professional development with fellow principals targeted toward impacting teachers' classroom practices. Recommendations include differentiation by school grade configuration, as well as incorporating larger teams of secondary principals. [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/en-US/products/dissertations/individuals.shtml.]