This qualitative case study explored elementary school principals' perceptions regarding the principal's role in teacher collaboration. The purpose of this study was to understand the role of a principal in teacher collaboration. The problem addressed by this study is increasing understanding of the role school leadership plays in developing collaborative cultures for teachers. It explored what principals identify as essential strategies in establishing a collaborative culture and how teacher collaboration impacts the elementary school principal's role as an instructional leader. Specifically, this qualitative case study explored elementary school principals' perceptions regarding the principal's role in developing and supporting teacher collaboration. The data collected reveals elementary school principals and teachers are affected by this problem. The conceptual framework applied supports the idea that principals are responsible for building collaborative cultures and highlights the principal's critical role. This study included elementary school principals from the same school district in Washington with at least one year of experience as a principal. Data from principal interviews and documents was collected and then annotated, highlighted, coded, and sorted. The data was carefully reviewed and analyzed for themes to emerge. Data analysis revealed six common themes for the research questions. The themes include data, resources and support, shared learning, student-focused, structures, and PLCs. The most significant implication of the findings is that principals must understand and prioritize the most influential components of teacher collaboration. Therefore, principals must prioritize the six themes when establishing teacher collaboration. I recommend that future researchers focus directly on how the principal could support teachers and cultivate a collaborative environment. [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.]