Research Findings: A difficulty for developmental researchers is disambiguating children's general maturation from the influence of schooling. In this study, we use a natural experiment to examine the influence of prekindergarten and kindergarten schooling experiences on the development of literacy and mathematics. Children (n=60) whose birthdates fell within 2 months of the state-determined cutoff date for prekindergarten and kindergarten entry were administered 4 subtests of the Woodcock-Johnson III Tests of Achievement in the fall and spring of the school year. Using hierarchical linear modeling coupled with propensity score matching, we found that children who were starting kindergarten and who had prior experience in prekindergarten had higher scores on measures of phonological awareness, early reading, and mathematics skills than did children who had not attended prekindergarten previously, even though they were essentially the same age. Fall vocabulary scores did not differ in relation to whether children had prekindergarten experience. In addition, although children who attended kindergarten as well as those who attended prekindergarten exhibited growth on all measures during the school year, children who attended kindergarten demonstrated greater gains in early reading and vocabulary during the school year. Practice or Policy: These findings highlight the potential of early schooling processes to facilitate children's intellectual growth. (author abstract)