Individuals with preexisting mental disorders are at increased risk for negative outcomes following a disaster and are one type of vulnerable subpopulation that requires special consideration in disaster preparedness, response, and recovery. We describe evidence of the increased risk for individuals with predisaster mental illness as well as tools for field triage, the critical role of partnerships in preparedness and response, and integration of mental health as a priority in emergency management systems. Considering individuals with predisaster mental disorders at each phase of a disaster may ameliorate some negative postdisaster outcomes, such as suicide.