Response to Intervention (RTI) is a research-based process in which students are provided timely intensive interventions. No longer adopting "wait to fail" models, this paradigm shift has challenged educators to employ systematic mathematics interventions which has been reported as challenging to implement within high schools. Therefore, the purpose of this study was to determine the perception of educators concerning a district-wide implementation to a RTI approach regarding student progress. Quantitative and qualitative data were collected from 31 educators integrally involved in a school district's first-year implementation of RTI in mathematics. This non-probability, purposive sample of educators was surveyed through the use of a questionnaire, interviews, and observational walkthroughs. Quantitative analyses revealed a statistically significant relationship between perceptions of educators regarding implementation of RTI during its first year and amount of RTI professional development. Qualitative analyses revealed themes noting strategies as successful included additional time, smaller group sizes, multiple sources of data, dedicated RTI coordinator, scripted program, focus on specific skills, games, and technology. Themes noted by educators as unsuccessful included the use of Path Driver, technology issues, age-appropriate programs, and lack of flexibility and strategic grouping. Recommendations included additional RTI professional development, professional development surrounding the universal screener, incentives, dedicated RTI coordinator for all high school locations, technical assistance, school flexibility upon placement in Tier II and III interventions, continuation of small groups, and utilization of the Inside Algebra intervention. [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/en-US/products/dissertations/individuals.shtml.]