The Third Wave was an experimental movement created by the high school history teacher Ron Jones in 1967 to explain how the German population could have accepted the actions of the Nazi regime during the rise of the Third Reich and the Second World War.

While Jones taught his students about Nazi Germany during his senior level Contemporary World History class, Jones found it difficult to explain how the German people could have accepted the actions of the Nazis. He decided to create a fictional social movement as a demonstration of the appeal of fascism. Over the course of five days (or nine, according to student Sherry Toulsey), Jones—a member of the Students for a Democratic Society (SDS), Cubberley United Student Movement sponsor and Black Panthers supporter—conducted a series of exercises in his classroom emphasizing discipline and community, intended to model certain characteristics of the Nazi movement.

As the movement grew outside his class and began to number in the hundreds, the experiment had spiralled out of control. He convinced the students to attend a rally where he claimed that the classroom project was part of a nationwide movement and that the announcement of a Third Wave presidential candidate would be televised. Upon their arrival, the students were presented with a blank channel. Jones told his students of the true nature of the movement as an experiment in fascism, and he presented to them a short film discussing the actions of Nazi Germany.

The project was adapted into an American film, The Wave, in 1981, and a critically acclaimed German film, Die Welle, in 2008.