Providing access to prekindergarten has been an important conversation in several states. Oklahoma has previously pioneered this effort, ensuring quality prekindergarten opportunities in nearly every district in the state. Over time, legislators and taxpayers have come to question the purpose and the effectiveness of prekindergarten, asking if this extra year of school is beneficial for the students who participate. This dissertation sought to identify long-term academic and socio-behavioral gains for students who attended a full academic year of an all-day prekindergarten program. Students who attended a full academic year of an all-day prekindergarten program were matched with like peers who attended no amount of prekindergarten through a propensity score matching design. Data was collected on measures of academic achievement and socio-behavioral development through the collection of reading and math fluency scores and discipline referrals over the students’ elementary school years. A hierarchical linear model and a logistic regression were used to analyze the data collected to determine if enrollment in an all-day prekindergarten program made a statistically significant difference for the students who participated over their later elementary school years. Results indicated that students who participated in a full academic year of an all-day prekindergarten program had statistically similar scores of academic achievement but had statistically stronger scores of socio-behavioral development than their matched peers.