The purpose of this qualitative case study was to explore how professional learning communities influence teacher morale and rigor in the classroom. Participants of the study consisted of six to eight core subject teachers from two 4-A high school campuses in southeast Texas. Two focus group interviews were conducted, one at each school, and participants had taught at the school for at least one school year. The researcher transcribed the information from the focus group interviews, analyzed it, and identified themes within the data. The findings suggested that professional learning communities create a collaborative environment based on trust and communication. The findings indicated that teacher morale was positively impacted with professional learning communities and classroom instruction was increased due to the PLC. Implications of practice include setting a vision for the campus that focuses on collaboration, develop a level of trust among the campus, provide time for collaboration, set goals or expectations for collaborative meetings, and have the administrator participate and be part of the collaborative meetings. [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.]