Educational organizations worldwide face challenges in selecting professional development models that meet the diverse and evolving needs of educators and students. Professional Learning Communities offer a means by which to address these needs. The problem addressed by this qualitative case study was the lack of a successful framework implementation and a shortage of time reserved for thorough implementation of professional learning at public and private schools alike. Through the lens of the experienced middle and high school educators at a school in the northeastern United States with a mature professional learning community, an effective framework is explored. Guided by the constructivist and constructionist theories of learning of Dewey, Piaget, and Vygotsky, along with the Senge's learning organizations theory and Fullan's practice theory perspective, the research questions focused on the teachers' perceptions of the PLC effectiveness and the extent to which the PLC practices aligned with the conceptual framework of PLCs as proposed by Hord. Data for this case study were collected using three methods: a professionally developed questionnaire administered to full-time teachers who had been with the school for at least two years, individual teacher interviews, and professional learning community meeting observations. Data originated in the questionnaire, followed by coding of meetings and interviews using NVivo software to identify themes and patterns. This study revealed that teachers perceived this model as supportive for organizational change, offering a feedback loop, strategic sharing and job-embedded teacher development with a mentoring component included. This case study brings successful processes and procedures to the forefront for developing, implementing, and sustaining an effective professional learning community. [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.]