This study investigated the implementation and impact of Reading First programs in 8 elementary schools across the state of Mississippi. The study assessed how principals, literacy coaches, and kindergarten through third grade teachers perceived the implementation of the Reading First program at their respective schools. Data from these three groups of research participants were analyzed to determine if there were differences in perceptions regarding program implementation. This study also examined if there was a relationship between participants' judgment about implementation and second and third grade students reading scores on the Mississippi Curriculum Test (MCT). This study employed descriptive, survey, causal-comparative, and correlational research. Descriptive data were used to describe research participants' gender, years of professional experience, highest degree held, and type of license held. Survey data were used to determine the perceptions of principals, literacy coaches, and teachers regarding the implementation fidelity of the Reading First program at their respective schools. An analysis of variance was used to determine if there were differences in the perceptions of the groups. Correlational statistics were used to analyze the possible existence of a relationship between principals', literacy coaches', and teachers' perceptions about implementation and second and third grade students' MCT reading scores. The study found that principals and literacy coaches perceived that the Reading First program was being fully implemented, but teachers believed that the program was being moderately implemented. There were no significant differences between the perceptions of principals, literacy coaches, and teachers. However, the study did reveal that principals, literacy coaches, and teachers had similar ratings regarding the implementation of specific Reading First program components. There was no correlation between perceived implementation fidelity of the Reading First program and students reading test scores on the MCT. Survey results revealed that most schools had fully implemented: (a) the uninterrupted, 90 minute reading block, (b) the 5 core elements of reading, (c) instructional strategies, and (d) support for struggling readers. Additionally, survey results indicated that schools need to strive toward fully implementing: (a) appropriate assessment strategies, (b) professional development activities that focus on reading instructional content and (c) instructional support activities. [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.]