Teaching reading in the mainstream classroom is a challenge. This challenge is compounded when trying to meet the needs of English language learners. Recently, Response to Intervention (RTI) has been suggested as a framework for classroom teachers to use in order to meet the wide range of needs of their students. The purpose of this study was to evaluate the effectiveness of an RTI reading instructional model when used with English language learners (ELLs) in mainstream classrooms. A mixed-method, quasi-experimental, pre/post design was implemented. A purposive sample was drawn from third grade students in schools that integrated ELLs and native English speakers. Dynamic Indicators of Basic Early Literacy Skills (DIBELS) and the Developmental Reading Assessment (DRA) were used to assess Reading achievement. Student reading assessment scores from the end of second grade were used as a covariate. Data were analyzed using MANCOVA. Further analysis of the ELLs included in the study was conducted using MANCOVA with Assessing Comprehension and Communication in English State-to-State (ACCESS) reading subsections as a covariate. The results of this study showed that ELLs in schools implementing reading RTI were able to achieve predicted reading benchmark levels at the same rate as native English speakers in the same schools. Overall, the number of students reaching benchmark levels was nearly equal in RTI and comparison schools; however, RTI schools had a greater number of ELLs reaching the benchmark. ELLs in RTI schools made the greatest gains in reading scores between assessments as compared to all other groups in the study. [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.]