This study examines the effects of universal public pre-kindergarten for 3-year-olds (Pre-K3) on later public education outcomes, including enrollment, school mobility, special education status, and in-grade retention from kindergarten through second grade. While universal pre-kindergarten programs typically target 4-year-olds, interest in expanding to 3-year-olds is growing. Using the centralized assignment lottery in the District of Columbia as the basis for a quasi-experimental design, we find that Pre-K3 students are more likely to persist in the public system and remain in the same school. These effects are strongest for residents of low-income neighborhoods and communities of color and for students enrolled in dual language programs. Overall, public Pre-K3 appears to stabilize children's early educational experiences, especially those starting furthest from opportunity.