This scoping review examines the impact of social media use (SMU) on sleep and mental health in youth, focusing on studies published between January 2020 and July 2023. The review highlights the negative effects of SMU on sleep and mental health, with both cross-sectional and longitudinal studies showing that excessive SMU can lead to poor sleep quality and increased risk of mental health issues such as depression and anxiety. The review also discusses the potential underlying mechanisms, including hyperarousal, light exposure, and the displacement of sleep. Despite some conflicting findings, the majority of studies support the association between SMU and adverse sleep and mental health outcomes. Future research should include prospective cohort studies with representative samples, use validated questionnaires and objective measurements, and design randomized controlled trials to better understand the complex relationships and establish causality. The review emphasizes the importance of promoting rational and beneficial SMU habits to improve sleep and mental health outcomes in youth.This scoping review examines the impact of social media use (SMU) on sleep and mental health in youth, focusing on studies published between January 2020 and July 2023. The review highlights the negative effects of SMU on sleep and mental health, with both cross-sectional and longitudinal studies showing that excessive SMU can lead to poor sleep quality and increased risk of mental health issues such as depression and anxiety. The review also discusses the potential underlying mechanisms, including hyperarousal, light exposure, and the displacement of sleep. Despite some conflicting findings, the majority of studies support the association between SMU and adverse sleep and mental health outcomes. Future research should include prospective cohort studies with representative samples, use validated questionnaires and objective measurements, and design randomized controlled trials to better understand the complex relationships and establish causality. The review emphasizes the importance of promoting rational and beneficial SMU habits to improve sleep and mental health outcomes in youth.