Working from a life course perspective, this study examined the links between mothers' fertility and relationship statuses and children's early school achievement and how these links varied by race/ethnicity and immigration status. Analyses of nationally representative data from the Early Childhood Longitudinal Study–Kindergarten Cohort revealed that children born to unmarried women scored lower than children of married women on math tests in kindergarten and first grade. This pattern was most attributable to associated differences in family income and parent education, and it was moderated by women's marital and relationship statuses after having their children. Evidence also suggested that the academic risks of some family structure pattern relative to continuously married parents might have been more pronounced for White children.