The primary goal of this study was to explore how educational interpreter supervisors defined, experienced and approached their work in K-12 schools in the United States of America. A secondary goal was to examine how they interpreted, navigated and enacted educational and interpreting policy in their jobs as supervisors. A comparative case study research design was used to collect data on the practices of four interpreter supervisors in alignment with three study axes: (1) supervisor practice, (2) policy engagement, and (3) change over time in educational interpreter supervision. A critical policy analysis lens was used to examine the policies supervisors thought were most salient to them and how they dealt with these policies practically and ideologically. Supervisor and policy profiles were created to compare data within and across participant cases. Data collected on supervisors' job characteristics and the three axes were analyzed using qualitative and non-statistical quantitative methods. Results showed that supervisors conducted their work collaboratively while centering the needs of deaf and hard of hearing students so students received interpreting services that were consistent and high quality. Accountability and professionalism were major themes across supervisor practice and policy. Supervisors engaged extensively with policy at micro and macro scales. The policies that most affected their work were those related to federal special education law, state law for educational interpreters, and codes of conduct, guidelines and professional credentials in the broader field of American Sign Language interpreting in the U.S. [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.]