Overview: Adolescents need about nine hours of sleep per night, yet most teens get far less. Inadequate sleep has consequences not only for academic performance but also for mental and physical health; it has been linked to lowered resilience and an increased risk of cardiovascular and metabolic diseases. It's imperative that assessment of sleep become a routine part of adolescent health care. An understanding of sleep physiology is essential to helping nurses better assess and manage sleep deprivation in this population. Sleep assessment involves evaluating the three main aspects of sleep: amount, quality, and architecture. The authors provide an overview of sleep physiology, describe sleep changes that occur during adolescence, and discuss the influence of these changes on adolescent health. They also provide simple questions that nurses can use to assess sleep and risk factors for disrupted sleep, and discuss patient education and other interventions.