Nationwide, the percentage of four-year-olds enrolled in state-supported preschool programs has more than doubled since the early 2000s as states dramatically increased their investments in early childhood education. Florida's Voluntary Pre-kindergarten Program (VPK), which began in 2005, has been a national leader with respect to preschool access. This paper provides the first evidence of the program's impacts. We measure the effect of VPK participation on the likelihood that children are retained at any point between kindergarten and third grade. Using an instrumental variables approach, we leverage local program expansion and detailed student-level data on eight cohorts of children, four of which were of preschool age in the years before VPK was implemented and four of which had access to VPK programs. The results indicate that VPK did not lead to changes in the likelihood that children complete the third grade without ever being retained. We do find, however, that VPK led to a change in the timing of retention. Specifically, the program led to a drop in the likelihood that children were retained during the kindergarten year, but this drop was counteracted by increases in retention in subsequent school years. Implications for policy are discussed.