Research has demonstrated the employment and earnings benefits accompanying educational attainment, and the relatively poor educational attainment and economic well-being of young people who transition to adulthood from foster care. Policymakers' concern over these poor outcomes has long been reflected in U.S. child welfare policy, most recently in the provisions of the 2008 Fostering Connections to Success Act allowing states to claim federal reimbursement for extending foster care from age 18 to age 21. While the policy of allowing youth to remain in foster care past age 18 has promise as a strategy for helping them continue their education, empirical evidence of its impact is lacking. Using data from a longitudinal study of youth (n = 732) who transitioned to adulthood from foster care, this study takes advantage of between-state policy variation in the age at which youth are required to leave care to assess the relationship between extended foster care and educational attainment at age 26. Distinguishing between not having obtained a high school diploma or GED, having only a high school diploma or GED, and having obtained at least one year of college, each additional year in care is associated with a 46% increase in the estimated odds that former foster youth will progress to the next level of educational attainment, controlling for a range of youth characteristics measured at ages 17–18. Background characteristics including youth's gender, race, employment, parenting, educational performance and aspirations, and indicators of behavioral health problems are also associated with educational attainment in early adulthood.