The purpose of this multiple case study was to examine the mentoring relationship between principals and their teachers in regards to instructional practice at three demographically diverse elementary schools. Multiple data sources were used to conduct qualitative research which resulted in extensive data collection and analysis. The collection of data was conducted through direct observations, semi-structured interviews, and a review of documents provided by each research site. This case study used the theories of adult learning, instructional leadership and transformational leadership to explain the findings, provide focused implications for mentoring processes between principals and teachers, and to influence the direction of future research on the central phenomenon. Data analysis involved the direct interpretation and categorical aggregation of themes and sub-themes through a coding process. The themes identified were providing support for teachers, engaging in formal and informal mentoring, and maintaining collaborative communication. Findings were also triangulated through cross case analysis. The specific sampling strategies used for this study were maximum variation sampling and criterion sampling. Maximum variation was employed to select three diverse sites based on demographics and location. Through criterion sampling, a total of twelve individuals were selected across all three sites to participate in the study. The participants included one principal and three teachers from each site who responded to interview questions and were observed as they interacted with colleagues and students in their settings. Research findings revealed that principals supported their teachers through positive vocabulary, instructional and material supplies, and emotional encouragement. Formal and informal mentoring practices were also evident among all research participants, in addition to collaborative communication between the principals and teachers. The findings were generally consistent with slight variations among three contrasting demographic settings based on the socio economic levels of low, middle, and high income classes. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]