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.

The experiment took place at Cubberley High School in Palo Alto, California, during the first week of April 1967. Jones, finding himself unable to explain to his students how the German people could have claimed ignorance of The Holocaust, decided to demonstrate it to them instead. Jones started a movement called "The Third Wave" and told his students that the movement aimed to eliminate democracy. Jones postulated that democracy's focus on individuality was against mankind's "authoritarian" nature, which he aimed to emphasize with the movement's motto: "Strength through discipline, strength through involvement."

Although the experiment was not well documented at the time, it was briefly mentioned in two issues of the Cubberley High School student newspaper, The Cubberley Catamount. A contemporary issue of the paper contains a more detailed account of the experiment, published just days after its conclusion. Jones wrote a short story about the experiment, first published 1976, some nine years after its conclusion. Subsequent articles by other authors followed, some featuring interviews with Jones and the students involved.

The experiment began with simple alterations such as proper seating. He wrote "Strength Through Discipline" on the classroom's chalkboard, then enforced strict classroom discipline while speaking about the importance of discipline. The procedures were simple. Students were expected to sit at attention before the second bell, had to stand up to ask or answer questions and had to do so in three words or fewer, and were required to preface each remark with "Mr. Jones". He drilled them on their adherence to these rules. Jones intended only a one-day experiment.

Jones decided to continue the experiment after observing his students' strict adherence to the previous day's rules. He added "Strength Through Community" to the chalk board, and named his movement "the Third Wave". Jones based the name of his movement on the supposed fact that the third in a series of waves is the strongest. Jones created a salute involving a cupped hand reaching across the chest toward the opposite shoulder, resembling a Hitler salute. He ordered class members to salute each other both in and outside of the class. Jones then assigned each of his students an individual assignment, such as designing a Third Wave banner, stopping non-members from entering the class, or recruiting their friends to join the movement.