Adolescents' Social Media Use (SMU) is one of the most prominent challenges for parents today. Many parents are concerned about the potential dangers associated with SMU, including mental health problems. For adolescents, however, social media represent a highly personal context falling outside of parents' legitimate authority. Because SMU is a highly sensitive theme in parent-adolescent interactions, it is essential to examine whether parents can be constructively involved in adolescents’ SMU. This project will advance the limited literature on this topic in three ways. First, it aims to provide a comprehensive picture of parents’ potential role in adolescents’ social media, thereby attending to parents’ direct management of adolescents’ SMU, the quality of their general parenting style, and parents' own SMU. Second, because peers play a highly influential role in adolescents' SMU, this project will examine parents' role in a more contextualized fashion, thereby considering the interactive interplay between parents and peers in adolescents’ SMU. A third aim of this project is to provide a more dynamic picture of the roles of parents and peers in adolescents’ SMU by examining bidirectional associations between parental behaviors, peer experiences, and adolescents’ SMU across different time-scales. These aims will be addressed with longitudinal and experience-sampling methodology among early adolescents transitioning from elementary school to high school.