Professional learning communities (PLC) are one strategy aimed at facilitating teacher professional development, with a focus on increasing student achievement. This mixed methods study investigated the impact of professional learning on student achievement. A total of 6 teachers and 121 students recruited from the third and fifth grades of a large elementary school located in the southeastern United States participated in the study. Teachers in this study engaged in professional learning sessions focused on improving reading fluency and math instruction based on the conceptual framework of PLC application synthesized by Paratore. Two assessments were used to monitor student achievement. Dynamic Indicator of Basic Early Literacy Skills (DIBELS) was used to assess reading and the Online Assessment System (OAS) was used to assess math. These assessments were given to the same subjects twice. T-test analysis was performed to determine if student achievement increased in the classes of teachers participating in the study. Qualitative data gathered through interviews and classroom observations were analyzed and coded using three repeating themes: ineffectiveness of professional learning, implementation of required professional learning, and the effectiveness of professional learning on classroom instruction. The outcomes of the study revealed significant increases in student achievement after professional learning sessions and the importance of properly implementing strategies learned. This study contributes to positive social exchange by helping to inform the professional development programs for teachers based on empirically tested interventions that support demonstrable changes in student learning. [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.]