The purpose of this literature review is to provide an overview of the research on sleep problems in autism spectrum disorder. Topics explored are the prevalence of sleep problems, the importance of studying sleep problems, as well as the objective and subjective measures used to measure sleep. Research on the relationships between sleep problems and parental stress and psychological distress, developmental regression, language and communication, adaptive behavior, autism severity, challenging behavior, comorbid psychopathology, attention deficit/hyperactivity disorder, gastrointestinal symptoms, epilepsy, and sensory issues is also discussed. Age-related variations in sleep problems are also examined. Finally, recommendations for treatment are given as well as areas where future research is needed.