The World Federation of Democratic Youth (WFDY) is an international youth organization, and has historically characterized itself as left-wing and anti-imperialist. WFDY was founded in London, United Kingdom in 1945 as a broad international youth movement, organized in the context of the end of World War II with the aim of uniting youth from the Allies behind an anti-fascist platform that was broadly pro-peace, anti-nuclear war, expressing friendship between youth of the capitalist and socialist nations. The WFDY Headquarters are in Budapest, Hungary. The main event of WFDY is the World Festival of Youth and Students. The last festival was held in Sochi, Russia, in October 2017. It was one of the first organizations granted general consultative status with the United Nations Economic and Social Council.

The World Festival of Youth and Students is an international event organized by the World Federation of Democratic Youth (WFDY) and the International Union of Students after 1947.