This report evaluates the impact of the Professional Learning Communities (PLC) at Work® process on student academic achievement over a three-year period in Texas public schools. Drawing on linked administrative data from the University of Houston Education Research Center (UH-ERC), the study uses a quasi-experimental approach to compare achievement trends in Model PLC at Work® Schools with those in non-designated schools. We estimate effects on math and reading performance using statewide standardized assessment data, disaggregating results by school level and student population. Findings indicate that gains in student achievement emerge gradually once schools begin their implementation of PLC at Work® practices, with the largest effects occurring in the designation year. Positive impacts are observed across our study sample (elementary and middle schools), with notable gains among economically disadvantaged students and English learners. These results suggest that the ongoing, sustained implementation of the PLC at Work® process by educators and administrators in the schools themselves is associated with measurable improvements in academic performance across a variety of grade levels, contents, and campus demographics. Given the observed trajectory of impact, school and district leaders may wish to consider long-term strategies for supporting and maintaining PLC at Work® implementation to promote continuous instructional improvement that leads to increased student achievement.