The Youth International Party (YIP), whose members were commonly called Yippies, was an American youth-oriented radical and countercultural revolutionary offshoot of the free speech and anti-war movements of the late 1960s. It was founded on December 31, 1967. They employed theatrical gestures to mock the social status quo, such as advancing a pig ("Pigasus the Immortal") as a candidate for president of the United States in 1968. They have been described as a highly theatrical, anti-authoritarian and anarchist youth movement of "symbolic politics".

Since they were well known for street theatre and politically themed pranks, they were either ignored or denounced by many of the "old school" political left. According to ABC News, "The group was known for street theater pranks and was once referred to as the 'Groucho Marxists'."