Sexual assault in correctional facilities is a public health concern during incarceration and post-release. Much research quantifies the extent of the problem among adults in jails and prisons, youth in juvenile facilities, and youth in jails and prisons. Beyond these numbers, there are varying levels of evidence regarding risk or protective factors. There is a history of research on sexual assault among adult carceral populations, an emerging literature among youth in custody, and scant work to understand the risks associated with sexual assault among youth housed in jails and prisons. This chapter first takes stock of recent prevalence estimates of sexual assault among these groups to better understand the problem. After the extent of the problem is outlined, the feasibility of applying research evidence to reduce risk of sexual assault is discussed.