This paper explores the importance of the home and school environments in explaining the gender gap in disruptive behavior. We document large differences in the gender gap across key features of the home environment--boys do especially poorly in broken families. In contrast, we find little impact of the early school environment on non-cognitive gaps. Differences in endowments explain a small part of boys' non-cognitive deficit in single-mother families. More importantly, non-cognitive returns to parental inputs differ markedly by gender. Broken families are associated with worse parental inputs and boys' non-cognitive development, unlike girls', appears extremely responsive to such inputs.