In "Self-Efficacy: The Exercise of Control" (1997), Albert Bandura writes, "Teachers operate collectively within an interactive social system rather than as isolates" (p. 243). Bandura's attention to the existence of the communal systems that exist in schools is an appreciation shared by many educational reformers, especially those who advocate for the purposeful cultivation of professional learning communities (PLCs). Such learning communities are designed to produce vibrant professional cultures that positively influence student learning. Because PLCs are concerned with institutional psychology and the influence of environmental conditions on collective and individual consciousness, Bandura's Social Cognitive Theory (SCT) provides a valuable theoretical framework by which the dynamics of these communal systems can be better understood. Bandura (1986) defined Collective Teacher Efficacy (CTE), an important construct of SCT, as the shared belief in a school's capability to attain goals and accomplish tasks regarding achievement of students. SCT's triadic reciprocality illuminates how individuals within school settings learn, think, and behave and is therefore a valuable framework for understanding the reciprocal relationship between PLCs and CTE. While both constructs have been studied separately in recent years, few research studies have endeavored to understand the relationship between the two. This quantitative survey study demonstrated that a strong positive relationship exists between the five dimensions of PLCs and the construct of CTE. These findings have important implications, not only for other researchers interested in these constructs, but also for school leaders endeavoring to cultivate vibrant professional cultures focused on student learning, continuous improvement, personal mastery, and systems thinking. [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.]