Evidence exists suggesting that most sexual aggression against older adults occurs in long-term care facilities. Fellow residents are the most common perpetrators, often demonstrating inappropriate hypersexual behavior caused by dementing illness. This resident-to-resident sexual aggression (RRSA) is defined as sexual interactions between long-term care residents that, in a community setting, at least one of the recipients would be likely to construe as unwelcome and that have high potential to cause physical or psychological distress in one or both of the involved residents. Although RRSA may be common, and physical and psychological consequences for victims may be significant, this phenomenon has received little direct attention from researchers. This is a review of the existing literature and relevant related research examining elder sexual abuse and hypersexual behavior that describes the epidemiological features of this phenomenon, including risk factors for perpetrators and victims. The legitimate and recognized need for nursing home residents, even those with advanced dementing illness, to express themselves sexually makes preventing and managing sexual aggression in nursing homes more challenging. This review discusses the ethical dilemma this situation creates and the need to evaluate the capacity to consent to sexual activity of residents with dementing illness and to re-evaluate capacity as the diseases progress. Suggestions are offered for managing incidents of RRSA and for future research, including the importance of designing effective interventions.