Despite growing evidence of the benefits of delayed school start times in adolescents, only a fraction of high schools globally – including US, Europe and Asia – have adopted later starts. The disadvantages of earlier school times for adolescents elicit primary concerns of decreased academic performance and well-being with a potential for the development of mental health conditions. In this impact paper, we discuss the current evidence and contributing mechanisms regarding insufficient sleep and circadian misalignment related to adolescent school schedules. We conclude by summarizing the obstacles to implementing later school start times and provide recommendations for policy change and potential alternatives to better promote better sleep hygiene and well-being among adolescents.