Multi-Tiered System of Supports is a comprehensive framework that unites colleagues of various backgrounds together in pursuit of a common goal to support students with evidence-based interventions to meet their individual needs in the school setting. The problem addressed in this study was the lack of professional development training teachers and support staff receive in the area of MTSS implementation. The purpose of this qualitative case study was to better understand the perceptions of teachers and support staff regarding what professional development training they have had, and what training they feel they need, in order to effectively implement MTSS. Implementation science served as the conceptual framework for this study. The literature identified such themes as understanding MTSS, interdisciplinary roles in MTSS, professional development training in MTSS, data-driven decision-making in MTSS, barriers to MTSS implementation, and fidelity and sustainability of MTSS. This study utilized a qualitative case study to examine the perceptions of ten teachers and two support staff for a total of twelve participants at a small, rural intermediate school in Northeast Florida. The researcher collected and analyzed data from a demographic survey, semi-structured interviews, and a focus group. Data triangulation was achieved through the use of multiple data collection methods. Based on the results of this study, recommendations included prioritizing professional development, establishing a district-wide alignment of MTSS goals, procedures, documentation, and evaluation, and school leaders establishing a high level of collaboration among school professionals to successfully implement MTSS. Recommendations for future research include conducting this study on a larger scale to contain the perceptions of administrators and instructional coaches, as well as conducting the interviews and focus group session in person, rather than virtually, to capture more in-depth responses from participants. [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.]