The purpose of this qualitative case study was to understand how teachers experience a stance toward inquiry through participation in Professional Learning Communities (PLCs). In order to meet this objective, the following questions framed this research: (1) How do individual teachers make meaning of the epistemological and dialogic aspects of their PLC's inquiry stance toward student data? (2) How do teachers interpret the influence of their personal inquiry stance toward student data on the stance of their PLC? and (3) How do teachers interpret the influence of external supports and constraints on their PLC's inquiry stance toward student data? The site of this research was a mid-sized Midwestern high school. The school had used the PLC structure for several years prior to this research. However, a new principal and assistant principal were hired for the 2016-2017 school year, which brought changes to the school's PLC processes. Eight teachers from five PLCs participated in qualitative, semi-structured interviews. Each participant was interviewed two times over the course of the second semester of the 2016-2017 school year. In addition, three PLCs were observed in meetings during the same time period. Finally, district, school and PLC documents were analyzed. Findings revealed that participants believed in an optimistic premise that professional collaboration had the potential to improve instruction and student learning. However, differences in the approach to knowledge and practice between individual teachers and their colleagues in the PLC, as well as constraints specific to the school context prevented participants from engaging in inquiry based on student-learning data to the degree desired. Participants experienced their PLC's epistemological and dialogic inquiry stance toward student-learning data as a proving stance. Much of their PLC work centered around the development of student learning goals aligned to the Common Core curriculum. When student data was discussed in the PLC, participants experienced the data process as proving the effectiveness of past instruction and generalizing student understanding of past instruction. In addition to spending the majority of the PLC time on the development of student learning goals, participants described much of their conversation centering around task completion, with the PLC agenda directing the work. Differences in participants' experiences of stance toward knowledge and practice emerged from this research. Tension existed in how knowledge was privileged. Participant responses demonstrated a belief that a set of best practices for professional collaboration existed, and the teachers felt they were expected to learn these best practices and implement the practices in their work. Participants also placed value in knowledge gained through classroom experience, and some participants expressed concern that the knowledge gained through experience was not valued in the school system. The tension between formal knowledge in the form of best practices and knowledge gained through experience was described as a concern or frustration specific to the context of the school that made inquiry in PLC work much more difficult than anticipated. The frustration with the difficulty of implementation of PLC work and the tension between different stances toward knowledge and practice resulted in tangible negative effects on the participants in this study. Social relationships were damaged. Some teachers sought compliance with perceived directives and mandates. Other teachers decided to question those same perceptions. Still others remained committed to collaboration and waited for teachers they considered to be resistant to leave the school so that replacements could be hired with compatible beliefs. Despite the difficulties and concerns expressed, all the participants expressed a belief that collaboration with colleagues was important to them socially and professionally. Their concerns were with the nature of implementation not the nature of collaboration. Through purposeful discussions on data processes and the ways in which differing stances toward knowledge and practice influence perception, it remains possible for teachers to experience an increasing sense of collective efficacy in their collaborative work. The results of this study revealed four practical strategies for school leaders to promote collaborative inquiry in schools. These strategies include developing structures that support collaborative inquiry, developing a shared vision that supports collaborative inquiry, developing data processes that support authentic collaborative inquiry, and promoting political and social conditions that support collaborative inquiry. This study also revealed two implications for teachers who participate in PLCs. The strategies for teachers include on-going reflection on images of knowledge and practice and on-going engagement in learning. In addition, the findings revealed suggestions for the use of this case study in both administrator and teacher preparation programs. [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.]