The purpose of this qualitative case study was to explore assistant principals' leadership readiness levels and the relationship between a district-provided administrator development program (ADP) and those levels. The study took place in Lovely Independent School District, which is in southeast Texas. Research questions focused on perceptions of leadership readiness and the quality of the ADP currently implemented. The research was guided by existing literature regarding situational leadership theory (SLT) and the CIPP Model (Context Evaluation, Input Evaluation, Process Evaluation, and Product Evaluation). SLT requires leaders to consider the needs, strengths, and limitations of individuals in their charge before taking any strategic action. Specific to this study, the theory allowed for flexibility and routine communication between current assistant principals and the ones who lead the professional development sessions. The four core values of CIPP Model helped researchers determine if a product, in this case the approach to professional development of assistant principals, was meeting its intended outcomes. The data was collected through questionnaires completed by assistant principals and semi-structured interviews with assistant principals and the program facilitator. Results from the study indicated themes such as approaches to professional development (collaboration and networking), refining leadership skills (knowledge of curriculum and district practices) and supporting school stakeholders (members of the teaching staff, currently enrolled students, and the parents/guardians of those students). Findings contributed to program improvement in Lovely Independent School district and other organizations and to the body of literature on school leader support and development. [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.]