More children today are being raised in households with mothers who work for pay compared to a generation ago, when most mothers did not engage in marketplace work. This demographic change is important because it could affect children. In this article, the effects of early and recent maternal employment on a child's academic development are identified as measured by high school grades. Results suggest that whereas early maternal employment does not have an effect, recent maternal employment (during a child's adolescent years) significantly decreases grades. Results also show that the effects of maternal employment do not differ for boys and girls.