Professional Learning Communities (PLCs) have become a popular reform initiative for schools looking to increase student achievement. School district officials can find it difficult to implement and sustain Professional Learning Communities as some teachers are not accustomed to the levels of collaboration with peers involved. If implemented and carried out with fidelity, PLCs can lead to strong improvements in student achievement as well as teacher effectiveness (Vescio, Ross, & Adams, 2008). In this study, the researcher intended to determine if teachers and school level administrators in a school district in southern Louisiana were adapting to the PLC model by monitoring their perceptions of PLC function over time. The purpose of this study was to assess teacher and school level administrators perceptions of PLC implementation and compare it to previous perception data from an earlier study. This important data created longitudinal data showing the implementation of PLCs in this district over time. In addition, four interviews with key district leaders were conducted to determine the implementation plan at the district level. This information was combined to help the researcher make determinations regarding this district's implementation efforts. Ultimately, the researcher found no difference in the perceptions of teachers from the first study regarding PLC implementation to the second administration of the Professional Learning Communities Assessment-Revised (PLCA-R) survey four years later. The major conclusion reached by the researcher regarding this finding is that people progress in their understanding of PLCs while working in them. Educators grow from a procedural understanding to a conceptual understanding of PLCs which causes them to be more critical of the PLC work in their schools, thus influencing survey results. The researcher identified key themes through the interviews with key district leaders that are detailed in Chapter Five. All of this valuable information allowed the researcher to evaluate district initiatives to sustain and improve PLC efforts, determine the effectiveness of district-wide implementation efforts over time, and provide feedback to others implementing PLCs district-wide. [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.]