Background: Prekindergarten programs are instrumental for smooth transition to the primary grades. Although the prevalence of these programs has expanded, limited studies document the long-term outcomes associated with children's engagement in such programs and for specific content areas such as mathematics. Objective: This study predicted the longitudinal mathematics achievement of 458 students as they progressed through elementary and middle school, accounting for their participation in Georgia's prekindergarten (Pre-K) program at age 4. Method: Archived academic achievement data in mathematics were extracted from one school district in the southeastern United States. A multilevel approach was employed to account for the nesting of students within schools. Liner and logistic regression analyses were used to examine the long-term relationship between prekindergarten participation and mathematics achievement. Results: After controlling for the effects of race, sex, and poverty, results indicated that participation in Georgia's Pre-K program positively predicted mathematics achievement through seventh grade. For fourth through seventh grades, the odds of a Georgia Pre-K participant meeting the state's academic standards on the statewide standardized test were 1.67-2.10 times greater than the odds for a nonparticipant. Conclusion: Although the reported effect sizes were small, children's participation in the Georgia Pre-K program had a long-term influence on their mathematics achievement through elementary and middle school, providing evidence of sustained benefits of a state-funded prekindergarten program. Quality learning experiences during the early years might provide skills and knowledge that serve as building blocks for later mathematics achievement.