Cyberbullying is a growing public health concern given its increasing prevalence, connection to mental health problems, and broader concerns about youth social media use. In this review, we define cyberbullying and its forms and provide information on prevalence and trends. We then contextualize cyberbullying within the larger research literature on digital technology use and mental health, detailing how this relationship varies depending on individual characteristics and how the technologies are being used. We then summarize the research on concurrent and long-term impacts of cyberbullying victimization and perpetration on internalizing and externalizing symptoms as well as the impacts on youth well-being. Mediating and moderating mechanisms that exacerbate risk and protect youth from adverse mental health impacts of cyberbullying are then explored. The evidence supporting cyberbullying prevention in school-based contexts and involving families is then presented. Finally, we discuss challenges in existing research, areas in need of further empirical investigation, and implications for practice and policy.