This review provides an overview of triaging critically ill or injured patients during mass casualty incidents due to events such as disasters, pandemics, or terrorist incidents. Questions clinicians commonly have, including “what is triage?,” “when to triage?,” “what are the types of disaster triage?,” “how to triage?,” “what are the ethics of triage?,” “how to govern triage?,” and “what research is required on triage?,” are addressed.