Although there are some federal and state statutes and regulations regarding principal evaluation systems, there are a variety of principal evaluation systems across the nation and in California. California's principal evaluation system is at the district level, meaning that implementation and effectiveness rest solely on the district. A district in Southern California utilizes a Squad Model of principal evaluation. The Squad Model is a principal evaluation system used to provide feedback, coaching, and support to principals in the district. Three to six principals are grouped in a Squad, led by the principal's immediate supervisor called the Squad Leader. The primary purpose of the program evaluation was to conduct a summative evaluation of the implementation and intended outcomes of the Squad Model. This evaluation employed a mixed-methods approach to answering the program evaluation questions. The program evaluation collected data using surveys and semi-structured interviews. The findings of the program evaluation were Squad Leaders and principals reported that collaboration, coaching, and support had increased due to the Squad Model. Principals reported that their effectiveness and instructional leadership had increased because of the Squad Model. The District's senior leadership, Squad Leaders, and principals reported the value of the Squad Model in their respective work. Finally, principals and Squad Leaders reported highly valuing the key activities or components of the Squad Model. [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.]