In the United States, legislators have created policies to hold school personnel accountable for the academic success of all students. However, many students with disabilities working toward a high school diploma have not demonstrated progress on local or national standardized assessments. The purpose of this qualitative case study was to explore the ways that high school principals in a Mid-Atlantic school district provided leadership practices to support the academic achievement of students with disabilities. Burns and Bass's transformational leadership theory informed this study. Data were collected via semistructured interviews with eight high school principals and a review of archival test data. A priori and open coding were used to distill specifics related to the barriers facing high school principals and the practices they employed to lead school improvement of special education outcomes. Participants identified leadership actions and behaviors aligned with transformational leadership and best practices for overall school improvement. They indicated they needed to address special education support more specifically. Some principals indicated staff needed more capacity to address the needs of special education students; others felt time was the primary barrier because teachers were overwhelmed with paperwork and other tasks. Additional preparation and ongoing training for principals and teachers focused on improving instruction, monitoring, and accountability related to the needs of students with disabilities were desired. These results may encourage positive social change by enhancing how principals support students with special needs and by informing district leaders of ways they can support principals to improve the academic outcomes of students with disabilities. [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/en-US/products/dissertations/individuals.shtml.]