Parents may have important effects on their children, but little work in economics explores whether children's schooling opportunities crowd out or encourage parents' investment in children. We analyze data from the Head Start Impact Study, which granted randomly-chosen preschool-aged children the opportunity to attend Head Start. We find that Head Start causes a substantial increase in parents' involvement with their children--such as time spent reading to children, math activities, or days spent with children by fathers who do not live with their children--both during and after the period when their children are potentially enrolled in Head Start. We discuss a variety of mechanisms that are consistent with our findings, including a simple model we present in which Head Start impacts parent involvement in part because parents perceive their involvement to be complementary with child schooling in the production of child qualities. (author abstract)