The anti-nuclear movement is a social movement that opposes various nuclear technologies. Some direct action groups, environmental movements, and professional organisations have identified themselves with the movement at the local, national, or international level. Major anti-nuclear groups include Campaign for Nuclear Disarmament, Friends of the Earth, Greenpeace, International Physicians for the Prevention of Nuclear War, Peace Action, Seneca Women's Encampment for a Future of Peace and Justice and the Nuclear Information and Resource Service. The initial objective of the movement was nuclear disarmament, though since the late 1960s opposition has included the use of nuclear power. Many anti-nuclear groups oppose both nuclear power and nuclear weapons. The formation of green parties in the 1970s and 1980s was often a direct result of anti-nuclear politics.
Scientists and diplomats have debated nuclear weapons policy since before the atomic bombings of Hiroshima and Nagasaki in 1945. The public became concerned about nuclear weapons testing from about 1954, following extensive nuclear testing including the Castle Bravo disaster. In 1963, many countries ratified the Partial Test Ban Treaty which prohibited atmospheric nuclear testing.