A recent study conducted by the National Staff Development Council (NSDC) has found that teachers who participate in high quality professional learning communities (PLC) are provided with on-going professional development that elicit focus on learning, a collaborative culture, collective inquiry, action orientation, commitment to continuous improvement, and results orientation (Wei, Darling-Hammond, Andree, Richardson & Orphanos, 2009; DuFour, Eaker, & DuFour, 2005; Hord & Sommers, 2008). Therefore, this study explored how principals and teachers who actively lead and participate in effective PLCs construct new knowledge to improve classroom practice and student achievement through the social interactions embedded in high-quality PLCs. This qualitative ethnographic study used anecdotal field notes and interviews to collect, analyze, and describe the data recovered from 23 observations and 11 formal and informal interviews conducted in two private early childhood education schools. The two educational sites and participants were purposefully selected using theory or concept sampling. The data were analyzed holistically, leading to a rich description of common themes and patterns as well as triangulating content validity methodologically and thematically. Findings culminated in a conceptualization of characteristics and strategies found in high quality PLCs that allow for the social construction of new educational knowledge to occur. Results suggest that educational leaders and policy makers should design and implement PLCs that foster collaboration, collective inquiry, and dialogic exchanges that provided teachers with the opportunity of constructing new meanings about education. Recommendations for guiding high quality PLCs are provided. [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.]