Parasomnias are a heterogeneous group of disorders that may result directly in criminal charges. This article provides a general description of these phenomena, the unique forensic aspects of parasomnia defenses, and an overview of accepted and contested approaches in the field of sleep forensic medicine. This article is intended for both general and forensic psychiatrists who might be called upon to provide expert testimony in a crime that originates from a sleep disorder. [Psychiatr Ann . 2017;47(12):588–592.]