Using data from the 2003-2007 American Time Use Surveys (ATUS), we compare mothers' (N = 6,640) time spent in four parenting activities across maternal education and child age subgroups. We test the hypothesis that highly educated mothers not only spend more time in active child care than less-educated mothers but also alter the composition of that time to suit children's developmental needs more than less-educated mothers. Results support this hypothesis: not only do highly educated mothers invest more time in basic care and play when youngest children are infants or toddlers than when children are older, but differences across education groups in basic care and play time are largest among mothers with infants or toddlers; by contrast, highly educated mothers invest more time in management activities when children are 6 to 13 years old than when children are younger, and differences across education groups in management are largest among mothers with school-aged children. These patterns indicate that the education gradient in mothers' time with children is characterized by a "developmental gradient."