As a facilitator of professional development for preschool teachers, the author is continually faced with questions related to the great divide between theory and practice. Although most child care professionals learn that developmentally appropriate practices support the holistic growth of young children during their initial training, many teachers feel ill-equipped to implement these practices in their classrooms. Many even feel that school structures (i.e., policies and procedures, curriculum, assessment, etc.) are not set up to support this type of teaching. This article discusses how to support teacher development in a way that allows teachers' knowledge base to permeate their day-to-day practice. The author describes the development of Collaborative Learning Communities (CLCs) as one such area that can be a valuable tool for practical, site-based professional development.