This chapter discusses the peer-reviewed research literature on victimization and perpetration of campus sexual assault (CSA). It focuses on risk factors including gender and other demographics, alcohol and other drugs, and hooking up, as well as prevention efforts, including bystander-intervention programs. Research on CSA in the US began with the pioneering work of sociologists E. J. Kanin and D. G. Kirkpatrick in the 1950s. Student gender and sexual orientation are likely the strongest and most robust predictors of CSA victimization. Across studies of college students’ violence and victimization, many of the students who will perpetrate or experience CSA before or during college tend to either decrease or increase in risk soon after college matriculation. Among many institutional factors involved, the process of adjudicating cases of CSA is central and provides an example of feedback loops in the social ecology of campus culture.