Since 2011, the John W. Gardner Center for Youth and Their Communities at Stanford University (Gardner Center) has examined school-based outcomes for San Mateo County Preschool for All (PFA) students who went on to attend elementary school in Redwood City School District (RCSD). The Gardner Center has previously reported on PFA students' outcomes through kindergarten (2011 report) and first grade (2012 report). This study follows these students through third grade, providing a complete look at the Pre-K to third grade experiences of children who participated in San Mateo County's high-quality preschool program. PFA San Mateo County was established in 2004 as a five-year demonstration project aimed at reducing the achievement gap by supporting high-quality preschool programs for low income three- and four-year old children. Overall, the majority of PFA students were at-risk for academic failure due to low parent education levels, English language learner status, and low-income status. We used longitudinal data from the Gardner Center's Youth Data Archive (YDA) to link individual student records from PFA to their early elementary records in RCSD. This study follows 876 PFA students who enrolled in RCSD kindergarten immediately following their participation in PFA. Due to data limitations, this study compared PFA participants to children who we know from other research likely attended private preschool. (author abstract)