Not to be confused with Third-Worldism.
The Three Worlds Theory is a theory proposed by Mao Zedong in 1974 that categorizes the international system into three worlds. According to the theory, the first world includes the imperialist United States and the supposedly "social imperialist" Soviet Union. The second world includes Japan, Canada, and Europe. The third world includes China, Latin America, Africa, and the rest of Asia.