Middle school students in an urban school district located in the northeastern United States struggled to improve their academic performance. In response to this problem, the superintendent initiated a districtwide professional learning community (PLC); however, students' test scores in five schools declined. The purpose of this basic qualitative study was to explore school administrators' and teachers' perspectives of the influence that PLCs had on teachers' instructional practices to improve student achievement. Wenger's theory of the community of practice guided this study. A purposeful sample of two school administrators and six teachers, who completed PLC implementation training and participated in PLCs for at least 2 years, volunteered and participated in semistructured interviews. Data were analyzed through coding and theme development. Administrators need to create structures for time allocation for PLC members to share ideas, reflect on teaching practices, and discuss problems and for a variety of accountability measures for planning best approaches to improve student achievement. Teachers believed that instructional coaches and funding for teacher observation opportunities during class time might increase their instructional capacity. Based on the findings, a three-day professional development was created for administrators and teachers to improve and sustain the current PLC. This endeavor could contribute to positive social change if administrators initiate and support PLC teams, who share a collaborative culture, collective inquiry, actionable decision making, and a commitment to continuous improvement, as a platform to improve student achievement. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]