The role of the assistant principal in the public schools is under studied and undervalued. As the largest group of school administrators and as future principals in training, the assistant principals' socialization process begs understanding. This study questions the transition from teacher to assistant principal, accounting for the setting and context of the move into school administration. Through a qualitative, in-depth phenomenological interview study of six assistant principals in their first years as public school administrators, this study focuses on their lived experiences with the transition. The theoretical framework constructed to examine the lived experiences of these six recently transitioned assistant principals relied on a social constructivist world view, Van Maanen and Schein's (1979) Theory of Organizational Socialization and Bandura's (1977) Theory of Self-Efficacy, as well as the researcher's own experience and subjectivity. The analysis uncovered three major themes, assistant principal duties, relationships with teachers, and changing leadership perspectives. Implications are made calling for less focus on the assistant principal as manager and allowing more time for the development of instructional leaderships skills. Additionally, it was determined that social interactions may impede observation and evaluation of former teacher colleagues if the assistant principal is unable to overcome social entanglements. Lastly, it is recommended that assistant principals be provided opportunities to experience multiple leadership styles to aid in the formation of their leadership abilities. [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.]