This qualitative research study used narrative inquiry to explore the professional development experiences needed for assistant principals aspiring to the principalship as perceived by seven principals who lead effective Title I schools. Five research questions guided the investigation of professional development opportunities that principals of effective schools experienced as assistant principals. Principals were selected to participate in the study based on purposeful criterion sampling. The findings affirm that assistant principals need professional development opportunities focused on tasks and actions that develop transformational leadership competencies to be successful at the next level. Other findings include the importance of building instructional leadership capacity and being involved in the decision-making processes in real-life situations during the assistant principalship. Further, principals emphasized the intangible value of human connections and relationships. This study suggests that principals who practice transformational leadership must devote time, energy, and focus to understand the needs of the school community as well as the needs of the individuals within that community in order to overcome resistance to change, to encourage continuous improvement, and to establish trusting relationships. [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.]