The U.S. Department of Justice estimates that between 149,200 and 209,400 incidents of sexual victimization occur annually in prisons and jails. However, very few individuals experiencing sexual victimization during incarceration report these incidents to correctional authorities. Federal-level policy recommendations derived from the Prison Rape Elimination Act suggest mechanisms for improving reporting as well as standards for the prevention, investigation, and prosecution of prison-based sexual victimization. Despite these policy recommendations, sexual assault persists in prisons and jails, with only 8% of prisoners who experience sexual assault reporting their victimization. This review focuses on gaps in the existing research about what factors influence whether adult victims in incarcerated systems will report that they have been sexually assaulted. Using ecological theory to guide this review, various levels of social ecology are incorporated, illuminating a variety of factors influencing the reporting of sexual victimization during incarceration. These factors include the role of individual-level behavior, assault characteristics, the unique aspects and processes of the prison system, and the social stigma that surrounds individuals involved in the criminal/legal system. This review concludes with recommendations for future research, policy, and practice, informed by an ecological conceptualization of reporting.