This article explains why rates of sexual assault remain high on college campuses. Data are from a study of college life at a large midwestern university involving nine months of ethnographic observation of a women's floor in a "party dorm," in-depth interviews with 42 of the floor residents, and 16 group interviews with other students. We show that sexual assault is a predictable outcome of a synergistic intersection of processes operating at individual, organizational, and interactional levels. Some processes are explicitly gendered, while others appear to be gender neutral. We discuss student homogeneity, expectations that partiers drink heavily and trust their party-mates, and residential arrangements. We explain how these factors intersect with more obviously gendered processes such as gender differences in sexual agendas, fraternity control of parties, and expectations that women be nice and defer to men. We show that partying produces fun as well as sexual assault, generating student resistance to criticizing the party scene or menís behavior in it. We conclude with implications for policy.