Homicide is the second leading cause of death for young people, and exposure to violence has a negative impact on youth mental health, academic performance, and relationships. We demonstrate that youth violence, including bullying, gang violence, and self-directed violence, increasingly occurs in the online space. We review the literature on violence and online social media, and show that while some forms of online violence are limited to Internet-based interactions, others are directly related to face-to-face acts of violence. Central to our purpose is uncovering the real-world consequences of these online events, and using this information to design effective prevention and intervention strategies. We discuss several limitations of the existing literature, including inconsistent definitions for some forms of online violence, and an overreliance on descriptive data. Finally, we acknowledge the constantly evolving landscape of online social media, and discuss implications for the future of social media and youth violence research.[The original abstract for this article contains images that cannot be displayed here. Please click on the link below to read the full abstract and article.]