Broad consensus exists across the country and political spectrum that sexual victimization occurs inside prisons and that it should be prevented in accordance with basic human rights, especially inside institutions that are funded and operated by government. The challenging task is to confirm the speculation by measuring reliably the extent to which sexual victimization occurs inside prison and then to understand its causal structure in an effort to prevent it. This article addresses this challenge first by summarizing what is known about the prevalence of sexual victimization in the prisons of America and then by exploring attributes of the inmate or facility that elevate the likelihood of being sexually victimized while inside prison. This descriptive evidence provides the roadmap for more contextual research that is needed to explore the causal mechanism underlying sexual victimization. The predictive part of this article uses a data set on the self-reported victimization experiences of approximately 8,000 inmates residing in twelve male adult prisons, one sex offender treatment prison for males, and one female adult prison, all located in a single state.