agency of the United Nations (UN) Secretariat originally established in 1972 to coordinate international relief activities to countries struck by natural or other disasters. It is headed by a disaster relief coordinator who reports directly to the UN secretary-general and works closely with the United Nations Development Programme (UNDP).

Responding to requests from stricken states for disaster assistance, OCHA not only directs UN assistance but also mobilizes aid from nongovernmental organizations such as the International Red Cross (International Committee of the Red Cross). OCHA also functions as an information coordination centre. Since the 1980s OCHA has emphasized disaster preparedness and prevention and the execution of UNDP-assisted projects.