The present study investigated Oral Reading Fluency and its ability to predict academic achievement in language arts and mathematics on 6,484 first through fourth grade students. Student, teacher, and school information from the 2006-2007 academic school year was collected from databases maintained by Salt Lake City School District. The information indicated that the student sample was 45.3% Caucasian, 39.0% Hispanic, and 15.6% Other (Non-Caucasian, Non-Hispanic). Data on a variety of variables were collected on 6,484 students, 330 teachers, and 29 schools. Hierarchical linear modeling was used to analyze the data in a three-level model. The present investigation examined the impact of student, teacher, and school variables on Oral Reading Fluency, language arts achievement, and mathematics achievement. Findings indicated that there were significant differences between Oral Reading Fluency scores and the three ethnic student groups for language arts achievement and mathematics achievement. The results also indicated that the predictive power of Oral Reading Fluency decreased as grade levels increased. In addition, DIBELS Oral Reading Fluency predicted academic achievement in language arts and mathematics equally well for both English-Speaking students and English Language Learners. However, English- Speaking students outperformed English Language Learners in both language arts achievement and mathematics achievement. The results of the present investigation support the use of Oral Reading Fluency to predict academic achievement outcomes of culturally and linguistically diverse students. [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.]