"For valid disability determination to occur, a diagnostic team needs to be able to determine that a student has received appropriate instruction in the general education classroom" (Johnson, Mellard, Fuchs, & McKnight, 2006, p. 4.2). The purpose of the study was to determine whether a middle school Response to Intervention (RTI) program is being implemented with fidelity. The researcher used the RTI Essential Components Worksheet and the RTI Fidelity of Implementation Rubric as the evaluation tools. The research focused on how effectively the RTI process was implemented at the focus middle school. A qualitative method design was used in the study. Several focus groups and interviews were completed to gather information. In addition, archived data were assembled to evaluate the RTI process. The following research questions were used. (1) To what extent are assessments, especially in the areas of screening, progress monitoring, and supporting assessments, used to inform data-based decision-making? (2) To what extent are data-based decision-making processes used to inform instruction, movement within the multilevel system, and disability identification as far as state law is concerned? (3) To what extent does the RTI framework include a school-wide, multilevel system of instruction and interventions for preventing school failure? (4) To what extent are infrastructure and support mechanisms in place to meet the established goals, particularly knowledge, resources, and organizational structures necessary to operationalize all components of RTI in a unified system? (5) At what level does a system exist for collecting and analyzing data to measure fidelity and effectiveness of the RTI model? The findings were that the middle school implemented all components of the RTI process with adequate fidelity. The researcher's top recommendations include that curriculum materials for all core curriculum areas be research based, there should be evidence based secondary interventions in all content areas and grade levels, and there should be consistent implementation of opportunities on all grade levels for students who exceed benchmarks. [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.]