The purpose of this qualitative case study was to identify ways in which teachers' participation in a subject-specific music professional learning community (PLC) impacts instruction and assessment of musical skills. Previous studies have provided evidence of PLCs' impact on teaching and student learning in many subject areas, but little has been done to examine the impact on music education specifically. The conceptual base for this case study was the PLC framework as reported in school level research. The research question was focused on the experiences of elementary music teachers in a music-specific PLC in a suburban school district in a southwestern state. Data collection included interviews with participating music teachers and fine arts administrators, observation of PLC meetings, and document analysis. Data were analyzed using Hatch's typological analysis based on the components of PLCs outlined in the conceptual framework. The findings revealed overall positive impacts of PLC participation on teacher morale, student learning, and teaching practices. It was recommended that more collaborative time for PLC activities be designated by school administrators. These findings could lead to positive social change by empowering more teachers to implement PLC practices, and by doing so, teachers may be more likely to engage in their own professional development to improve their teaching practices, increase teaching morale, and enhance student learning in music. [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.]