Large-scale displacement takes place in the context of disaster because the threat or occurrence of hazard onset makes the region of residence of a population uninhabitable, either temporarily or permanently. Contributing to that outcome, the wide array of disaster events is invariably complicated by human institutions and practices that can contribute to large-scale population displacements. Growing trends of socially driven exposure and vulnerability around the world as well as the global intensification and frequency of climate-related hazards have increased both the incidence and the likelihood of large-scale population dislocations in the near future. However, legally binding international and national accords and conventions have not yet been put in place to deal with the serious impacts, and material, health-related, and sociocultural losses and human rights violations that are experienced by the millions of people being swept up in the events and processes of disasters and mass population displacements. Effective policy development is challenged by the increasing complexity of disaster risk and occurrence as well as issues of causation, adequate information, lack of capacity, and legal responsibility. States, international organizations, state and international development and aid agencies must frame, define, and categorize appropriately disaster forced displacement and resettlement to influence effective institutional responses in emergency humanitarian assistance, transitional shelter and care, and durable solutions in managing migration and resettlement if return is not possible. The forms that disaster-associated forced displacements are projected to take and corresponding national responses are explored in the Indian Ocean tsunami of 2004 in Sri Lanka, a massive disaster in a nation riven by civil conflict; Hurricane Katrina of 2005 in the United States, where the scale and nature of displacement bore little relation to hazard intensity; and the 2011 Great East Japan Earthquake, Tsunami, and nuclear exposure incident exemplifying the emerging trend of complex, concatenating, multihazard disasters that bring about large-scale population displacements.