This study proposes and tests hypotheses regarding the factors in public early-childhood education (ECE) policy that may explain local universal pre-kindergarten (UPK) policies. By analyzing district-level longitudinal data from the Wisconsin State Department and United States (U.S.) Census over two decades, the study examines the contextual factors associated with policy adoption. Among the three frames of ECE policy – social welfare, education, and family services – this study finds that the education frame, which emphasizes the goal of public ECE in improving all students’ educational outcomes, is the primary motivation for UPK in Wisconsin. The social-welfare frame, which posits that public ECE supports poor families, also appears to be associated with Wisconsin UPK policies. Additionally, the results show that UPK was not introduced to provide more child care for working parents, indicating that the family-service frame does not explain UPK. (author abstract)