Women who attain more education tend to have children with more educational opportunities, a transmission of educational advantages across generations that is embedded in the larger structures of families' societies. Investigating such country-level variation with a life-course model, this study estimated associations of mothers' educational attainment with their young children's enrollment in early childhood education and engagement in cognitively stimulating activities in a pooled sample of 36,400 children (n = 17,900 girls, 18,500 boys) drawn from nationally representative data sets from Australia, Ireland, U.K., and U.S. Results showed that having a mother with a college degree generally differentiated young children on these two outcomes more in the U.S., potentially reflecting processes related to strong relative advantage (i.e., maternal education matters more in populations with lower rates of women's educational attainment) and weak contingent protection (i.e., it matters more in societies with less policy investment in families).