Many feminist scholars argue that the seeming naturalness of gender differences, particularly bodily difference, underlies gender inequality. Yet few researchers ask how these bodily differences are constructed. Through semistructured observation in five preschool classrooms, I examine one way that everyday movements, comportment, and use of physical space become gendered. I find that the hidden school curriculum that controls children's bodily practices in order to shape them cognitively serves another purpose as well. This hidden curriculum also turns children who are similar in bodily comportment, movement, and practice into girls and boys-children whose bodily practices differ I identify five sets of practices that create these differences: dressing up, permitting relaxed behaviors or requiring formal behaviors, controlling voices, verbal and physical instructions regarding children's bodies by teachers, and physical interactions among children. This hidden curriculum that (partially) creates bodily differences between the genders also makes these physical differences appear and feel natural. Social science research about bodies often focuses on women's bodies, particularly the parts of women's bodies that are most explicitly different from men's-their reproductive capacities and sexuality (E. Martin 1987; K. Martin 1996; but see Connell 1987, 1995). Men and women in the United States also hold and move their bodies differently (Birdwhistell 1970; Henley 1977; Young 1990); these differences are sometimes related to sexuality (Haug 1987) and sometimes not. On the whole, men and women sit, stand, gesture, walk, and throw differently. Generally, women's bodies are confined, their movements restricted. For example, women take smaller steps than men, sit in closed positions (arms and legs crossed across the body), take up less physical space than men, do not step, twist, or throw from the shoulder when throwing a ball, and are generally tentative when using their bodies