The purpose of this study was to assess the perceptions of principals who serve as mentors for an internship program for aspiring principals at East Tennessee State University. Each mentor was interviewed to gather information about the internship program, the benefits of mentoring in the program, and what the mentors may have learned about their tacit knowledge as a result of the experience. Mentors and the professors in the Educational Leadership Policy Analysis department at ETSU may benefit from the findings as the design of the school leadership program continues to advance. Mentoring is an important component of training for aspiring and beginning principals because interns learn on the job in a supportive environment where they can take chances. Mentors also learn from the experience of being a mentor. The literature reviewed for this case study supported the need for standard-based mentoring programs. The ISLLC standards are an excellent example of standards that are used to provide structure and coherence for mentoring programs. Positive and negative outcomes for the mentor were reviewed to support the research. Leadership and the change process were also reviewed to support the importance of the mentor's role in the process we call mentoring. Several themes emerged from the analysis of data provided by mentor principals about mentoring aspiring principals. Mentoring resulted in reflection about the decisions the mentor makes during the day while explaining procedures to the intern. It was also found to be an experience that works best when a positive relationship is developed between the mentor and the intern; often leading to a relationship that lasts long after the internship is over. Principals examined their understanding of tacit knowledge and the possible ways tacit knowledge could be taught to their intern. [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.]