There is a growing body of evidence in the area of effectiveness of MTSS/RtI programs, specifically in the area of gender, classification and at-risk students. However, the body of evidence reflects that the impact of the RtI's effectiveness is minimal. More research that addresses the level of effectiveness of RtI programs is needed. Through the use of the Concerns-Based Adoption Model (CBAM) survey and focus groups, this study provides insights into how teachers, administrators, and RtI staff perceive and define a successful implementation of a RtI program in mathematics as it relates to students' MAP Growth data in UAE public schools. After COVID-19, implementing effective intervention models is a pressure that has been added to the teachers' workload and responsibilities by administrators, with the expectation of making it work. Teachers, leaders, and staff perception of RtI may impede a successful implementation of the framework; therefore, it is important to understand teachers, leaders, and staff perceptions on successful RtI implementation criteria. This research followed a sequential mixed research approach. The setting for this research consisted of selected public schools across the UAE. Results of the study found that MTSS/RtI was being implemented at some level within each school in the sample; however, the level of implementation varied across all schools. More specifically, results from the study provided evidence that some schools had a good understanding of RtI, but also that others misunderstood RtI, including its rationale, foundation, background, components, and implementation levels. Results of the study are discussed with a particular focus on the implications for further MTSS/RtI implementation. [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.]