Does an increase in a welfare mother's education improve her young child's academic performance or behavior? Positive correlations between mothers' educational attainment and children's well being, particularly children's cognitive development and academic outcomes, are among the most replicated results from developmental studies. Yet, surprisingly little is known about the causal nature of this relationship. Because conventional regression approaches to estimating the effect of maternal schooling on child outcomes may be biased by omitted variables, this study uses experimentally induced differences in mothers' education to estimate instrumental variable (IV) models. Data come from the National Evaluation of Welfare-to-Work Strategies Child Outcomes Study--an evaluation of mandatory welfare-to-work programs in which welfare recipients with young children were randomly assigned to either an education- or work-focused program group or to a control group that received no additional assistance. Findings suggest that increases in maternal education are positively associated with children's academic school readiness, and negatively associated with mothers' reports of their children's academic problems, but with little to no effect on children's behavior. Analyses were not able to determine whether the benefits of maternal education persisted over time, although they were able to test whether mothers' returns to schooling during their children's preschool years were more beneficial than returns during later years. Weak evidence indicates that mothers' reentry into school when children are young will have a lasting effect on children's academic problems. Supplemental data tables are appended, and a bibliography is also included.