Professional Learning Communities (PLCs) are an emerging form of professional learning used nationwide as a means for educators to focus on job-embedded learning. Extensive qualitative data have been compiled regarding the perception of educators and PLCs. However, little quantitative research has been conducted regarding the academic achievement of students who are protected under the Individuals with Disabilities Education Improvement Act (IDEIA, 2004) whose teachers participate in PLCs. A causal-comparative study compared the academic achievement of fifth-grade students who are protected under the special education umbrella (IDEIA, 2004). This study focused on two different Texas school districts, one of which had implemented PLCs for more than 3 years. The second school district had not implemented PLCs. Archival data were obtained from the Texas Education Agency (TEA) and Adequate Yearly Progress (AYP) for fifth-grade students being served in special education in reading and mathematics for both school districts. Teacher longevity was also compared between the two school districts. [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.]