The Peoples Temple Agricultural Project, better known by its informal name "Jonestown", was a remote settlement in Guyana established by the Peoples Temple, a US-based cult under the leadership of Jim Jones. Jonestown became internationally infamous when, on November 18, 1978, a total of 909 people died at the settlement, at the nearby airstrip in Port Kaituma, and at a Temple-run building in Georgetown, Guyana's capital city. The name of the settlement became synonymous with the incidents at those locations.

In total, 918 individuals died in Jonestown, all but two from apparent cyanide poisoning, a significant number of whom were injected against their will, in an event termed "revolutionary suicide" by Jones and some Peoples Temple members on an audio tape of the event, and in prior recorded discussions. The poisonings in Jonestown followed the murder of five others by Temple members at Port Kaituma, including Congressman Leo Ryan, an act that Jones ordered. Four other Temple members committed murder-suicide in Georgetown at Jones' command.

Terms used to describe the deaths in Jonestown and Georgetown have evolved over time. Many contemporary media accounts after the events called the deaths a mass suicide. In contrast, later sources refer to the deaths with terms such as mass murder-suicide, a massacre, or simply mass murder. Seventy or more individuals at Jonestown were injected with poison, and a third of the victims (304) were minors. Guards armed with guns and crossbows had been ordered to shoot anyone who attempted to flee the settlement as Jones lobbied for suicide.