Jonestown was the informal name for the "Peoples Temple Agricultural Project", an intentional community in northwestern Guyana formed by the Peoples Temple, a cult from California, United States, led by Jim Jones. It became internationally notorious in November 1978, when 918 people died in the settlement as well as in a nearby airstrip and in Georgetown, Guyana's capital. The name of the settlement became synonymous with the incidents at those locations.

On November 18, 1978, 909 Temple members died in Jonestown, all but two from apparent cyanide poisoning in an event termed "revolutionary suicide" by Jones and some members on an audio tape of the event and in prior discussions. To the extent the actions in Jonestown were viewed as a mass suicide, it is the largest such event in modern history and resulted in the largest single loss of American civilian life in a non-natural disaster until the events of September 11, 2001.