Why do babies need so much sleep? Is there a connection between poor sleep and attention deficits, risky decision-making, and behavioral problems in adolescents? Can sleep improve your memory? Is napping as effective as sleep? Can we stave off deterioration in cognition that occurs in older adulthood by treating sleep problems? We live in a society that is driven to work hard and sacrifice our sleep. It is, therefore, imperative that we begin to answer questions about the impact of decreased sleep on memory and cognition across the lifespan. The National Sleep Foundation reports that Americans get an average of 6.5 hours of sleep on weeknights, though 8 hours are recommended. Both men and women have decreased sleep (e.g., 67 percent of women report having poor sleep at least three nights a week). Studies of sleep in infants show that sleep deprivation begins in our earliest years, which may have consequences for infant learning and health. New studies show that two hallmarks of older adulthood, decreased sleep and cognitive decline, may be related. Moreover, sleep interventions can help reduce the decline in this age-group. This symposium brings new scientific discoveries about the impact of sleep on memory and cognition from the laboratory to the real world. We investigate the role of sleep on early brain development, infant language learning, adolescent and adult cognition and behavior, candidate mechanisms for sleep-dependent learning, and cognition in older adulthood.