This chapter describes the mental health impact of the 2004 tsunami in Southeast Asia. The psychological impact of the tsunami may have been aggravated by the ongoing political violence. Conflict areas often suffer from a diminished or overburdened public health infrastructure, which can make mental health resources scarce. The impact of the tsunami on the environment and economic systems was profound and widespread. The loss of livelihoods, homes, and the devastation of entire community networks, which normally would help one recover from loss, all aggravated the psychological impact of the tsunami. The magnitude of the tsunami's impact on mental health is documented in a number of studies and surveys in different parts of the affected region. Studies in the tsunami-affected areas showed increases in the prevalence of posttraumatic stress disorder (PTSD), anxiety, and depression. A number of programs are implemented to address the psychological and social needs of tsunami victims.