The mass casualty incident marks the ultimate challenge for emergency services at a mass gathering event. This chapter provides a thorough review of the unique challenges associated with the occurrence of a mass casualty incident in a mass gathering setting and summarizes a comprehensive, flexible framework to manage this specific scenario. In particular, we provide a detailed summary of the evidence and recommendations associated with the prevention, preparedness, response, and recovery efforts related to mass casualty incident management at a mass gathering event. Our discussion of prevention focuses on proper risk assessment practices and a recommended set of effective measures that can be used to promote crowd management within the mass gathering setting. Our section on disaster preparedness highlights the critical initial step to identify and engage all stakeholders associated with the mass gathering event and the particular disaster scenarios identified in the event’s risk assessment profile, as well as key measures to establish clear disaster plans and promote organized command and communication. Finally, specific recommendations are provided for efficient disaster response through the initial and longer-term phases, as well as for the recovery process that includes effective community support and psychological first aid for affected parties.