Growing evidence has linked center-based early care and education settings to improvements in children's cognitive skills. Additional research is needed to more carefully delineate when and for whom these associations are most pronounced. Using data from the Early Childhood Longitudinal Study, Birth Cohort (N = 6,350; Flanagan & West, 2004), this study examined whether the beneficial effects of center-based care settings for children's cognitive skills at age 5 differ by the age at which children experience these settings and for subgroups based on household income, parental education, and quality of the home learning environment. The results suggest that center-based preschool was supportive of the math and reading skills development of the sample as a whole. However, both center- and home-based care for 2-year-olds as well as 4-year-olds were beneficial for children from lower income, less educated, and less enriching family contexts, helping to diminish the cognitive skills gap between more and less advantaged children.