This qualitative case study aimed to explore teachers' perceptions of the impact of i-Ready on student reading achievement for students in Response to Intervention (RTI). In this qualitative case study, participants were given an opportunity to voice their point of view and perceptions of the impact of i-Ready, including the benefits and barriers they experience when implementing i-Ready as an intervention tool for struggling readers. The need to hear teacher voices and perspectives on an RTI intervention tool is essential to providing students with the best learning experience and growth results. The study included five elementary teachers who implement i-Ready as their only intervention tool for students in RTI. The participants were interviewed to give them an opportunity to speak about their perspectives on i-Ready's impact on student reading achievement. The results of the study showed that participants felt that the benefits of i-Ready on student reading achievement were that the program provides differentiation for students, data analysis for progress monitoring, is resourceful in offline resources, and is effective in helping students achieve milestones. The study revealed that the barriers to i-Ready were more about the systems that support its implementation, such as the need for ongoing professional development and adequate classroom time for the intervention block. [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.]