Earthquakes are unpredictable natural disasters caused by movements of tectonic plates at specific “fault lines” of the Earth’s crust. Large earthquakes cause significant numbers of deaths and injuries, along with large-scale damage to housing, infrastructure, and livelihoods. Tsunamis are massive “tidal” waves, most often due to underwater earthquakes. Earthquakes and tsunamis are associated with an elevated risk of mental disorders both acutely and in the long term. Western and North India, Pakistan, Nepal, and southern Afghanistan have witnessed large earthquakes in the recent past. Southern coastal India, Sri Lanka, and the Maldives experienced severe damage during the 2004 Indian Ocean tsunami. These events were followed by elevated rates of depression, anxiety, and post-traumatic stress disorder in affected communities. Persons who experienced direct exposure to the event, loss of housing or property, bereavement, or physical injury were more likely to experience psychological morbidity. This chapter provides an overview of research on the mental health sequelae of these disasters in South Asian populations and of the efforts made to treat them. It also explores the challenges and opportunities for “building back better” in terms of earthquake readiness and improved mental health care.