The research study was an evaluation of a professional learning community (PLC) and its effect on teachers and student achievement in a high school serving predominately Latino students. The study was a mixed research study that consisted of both quantitative and qualitative data. The quantitative data included school-wide and Latino student Academic Performance Index (API) and Adequate Yearly Progress (AYP) scores. The qualitative data sources were derived from faculty interviews and open-ended questions on the survey. The data were collected from 34 out of 50 (68%) faculty surveys and 29 out of 50 faculty rubrics (58%). Developing, implementing, and evaluating PLCs in a high school that served predominately Latino students led to increased API scores and increased AYP scores in math. AYP scores did not increase for English/Language Arts. Over half of the faculty (76%) reported PLCs as effective in developing standards based assessments, and 67.7% reported collaboration among teacher teams as effective for sharing best practices. Implications, recommendations for practice, and recommendations for future research are included. [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.]