International Physicians for the Prevention of Nuclear War (IPPNW) is a non-partisan federation of national medical groups in 63 countries, representing doctors, medical students, other health workers, and concerned people who share the goal of creating a more peaceful and secure world free from the threat of nuclear annihilation. The organization's headquarters is in Malden, Massachusetts. IPPNW was awarded the Nobel Peace Prize in 1985.

A nuclear holocaust, also known as a nuclear apocalypse, nuclear annihilation, nuclear armageddon, or atomic holocaust, is a theoretical scenario where the mass detonation of nuclear weapons causes widespread destruction and radioactive fallout. Such a scenario envisages large parts of the Earth becoming uninhabitable due to the effects of nuclear warfare, potentially causing the collapse of civilization, the extinction of humanity, and/or the termination of most biological life on Earth.