The focus of this practice-based research was to explore teachers' perceptions of implementation approaches to multitiered system of supports (MTSS). For more than 10 years there have been varied approaches for implementation of MTSS, which has caused a lack of guidance and support for teachers. Therefore, this qualitative descriptive study explored teachers' perceptions of implementation approaches to MTSS and its guidance and support provided to teachers. The two research questions in this study were based on how do teachers describe their perceptions about implementation approaches to MTSS and the guidance and support they received through the implementation of MTSS. The theoretical framework of the theory of reasoned action supported my analysis of teachers' descriptions and how their perceived attitudes, norms, and intentions possibly shaped their behavior in their implementation processes. The sample comprised of 12 elementary and middle school teachers in the state of Georgia with MTSS experience. Data collection methods included interviews and document training materials. A thorough content and descriptive analysis of the data were conducted manually and on NVivo. This resulted in 2,460 codes, four categories, seven themes, and 24 subthemes. The four themes aligned with RQ1 focused on how the MTSS specialist led systems and processes of MTSS implementation and the challenges in the process. The three themes aligned with RQ2 focused on data-driven guidance and support for MTSS implementation. The key implications of and recommendations of this research focused on the issues of leverage training, leadership development of the MTSS specialist, and utilization of the whole child team to increase the fidelity of implementation of the multitiered system of supports. [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.]