Adolescence is a time when biological processes regulating sleep and environmental factors, like the start of the school day, are often at odds, and can result in ill-timed, insufficient, and irregular sleep patterns in teenagers. To provide a broad understanding of these conflicting factors, this article reviews maturational changes to sleep regulation during adolescent development, as well as the changing psychosocial context that impacts sleep–wake behavior in this age group. Some consequences of insufficient sleep are also discussed, specifically highlighting the negative impact on daytime alertness, academic performance, and emotional or behavioral problems. The article ends with a brief overview of sleep disorders that typically emerge during the adolescent years.