The professional learning experiences of K-12 educators are a critical and complex part of continuously improving teaching and learning within a school. This case study brings to light the experiences of three teams of middle school teachers participating in a professional learning model called instructional rounds. The purpose of this research is to provide insight into how participating in instructional rounds impacted teachers' thinking about teaching and student learning in order to develop their classroom practice through reflection and inquiry. The data for this qualitative case study was collected through participant observations of instructional rounds and the analysis of related documents over an eight-month period, as well as through semi-structured interviews with 11 of the participating teachers. Key findings discussed in the case study begin with a description of how instructional rounds provided alignment and coherence of existing core practices and processes to transform knowledge of effective teaching into implemented action. Reasons teachers valued participating in instructional rounds discussed in the case study include teacher agency in setting goals relevant to their work, opportunities to see their colleagues teaching during classroom observations and time to debrief or make sense of what they saw. The findings further elaborate in describing how these shared experiences within the instructional round process supported teacher growth and change in practice. The final theme discussed in the case study is collective efficacy and how participating in instructional rounds impacted the relationships between the participants and their willingness to collaboratively improve teaching and learning in their classrooms. These findings reinforce the need for teachers to engage in authentic professional learning experiences connected to relevant classroom issues or goals they identify as important. Equally important, effective change in instructional practice is accelerated when teachers are provided ongoing opportunities to observe and analyze the teaching of their colleagues. [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.]