This descriptive study investigated the development of the 5 dimensions of the professional learning community model in 5 economically disadvantaged and diverse Texas elementary schools, which demonstrated improvement in student achievement on the Texas Assessment of Knowledge and Skills (TAKS) over a 5-year period. Each of the schools were given the highest performance rating of Exemplary during the 2008 school year according to criteria developed by the Texas accountability system and had changed from an Acceptable rating in 2004. The purpose of this study was to determine the level of the development of the 5 dimensions of the professional learning community model in improving exemplary Texas elementary schools and to identify and compare the possible commonalities and differences existing between the schools on the 5 dimensions of professional learning communities. The 5 dimensions of the professional learning community model investigated in this study include: 1) shared and supportive leadership, 2) shared values and vision, 3) collective learning and the application of learning, 4) shared personal practice and 5) supportive conditions (collegial relationships and structures). The method used in this study was a mixed method approach that employed a questionnaire, individual principal and teacher interviews and school performance documents to collect …