The purpose of this study was to discover the potential relationships between principals' special-education training and experiences and the academic growth of students with disabilities (SWDs). The study also investigated the differences between the academic growth of SWDs at schools where principals have completed a degree, minor, and/or licensure endorsement in special education and those who have not. The researcher conducted a mixed-methods study using semi-structured interviews and a researcher-created questionnaire. Seven principals in Tennessee were selected using purposive sampling, and 21 principals were secured using snowball sampling through interview participants' social networking groups (i.e., Principal Facebook Groups). The interview transcripts were analyzed using content analysis (an open-coding approach); descriptive statistics and frequency distributions were used to determine potential trends between principals' special-education training/experiences and SWDs' Tennessee Value-Added Assessment System (TVAAS) academic growth scores; and a Mann-Whitney U test was used to determine possible differences in SWDs' academic growth scores between schools with principals who had completed a degree, minor, and/or licensure endorsement in special education and those who had not. Several qualitative themes emerged: (a) pre-requisite and current special-education trainings matter; (b) understanding the Individualized Educational Plan (IEP) process matters; (c) understanding special-education research-based instructional strategies matter; (d) special-education background increases awareness (e) special-education staff and professional development is sufficient; and (f) all principals need inclusionary mindsets and practices. The quantitative results suggested a small but non-significant difference (U = 46.50, z = -0.624, p = 0.557) between SWDs' TVAAS academic growth scores from schools with principals who had a degree, minor, and/or licensure endorsement in special education (M = 2.73) and those who did not (M = 2.40). Principals in this study perceived that a background in special education would better equip principals to create a more inclusive and supportive learning environment for learners with exceptional needs. However, they also perceived that other factors--principals' relevant and timely professional development, their access and reliance on a quality special-education teacher/chairperson, their years of experience in their current school, and their level of commitment and ownership in supervising the special-education program of their school--may impact SWDs' academic growth, regardless of principals' special-education backgrounds. The findings of this study will inform educational stakeholders about principals' perceptions regarding the special-education knowledge and skills necessary in their current roles and what support they need to better promote the academic growth of SWDs. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]