Counterculture , a set of behaviors and beliefs that are radically different from those of mainstream society. The term is often used to refer to a movement that took place in the United States in the late 1960's and early 1970's that was built upon hallucinatory drugs, sexual permissiveness, unconventional dress, rock music, leftist politics, and opposition to the war in Vietnam. Its participants, mainly young adults, were commonly called hippies.

Although only a small number of persons actively participated in the counterculture, it exerted influence as antiwar sentiment increased, drug consumption increased, and many entertainers in popular music adopted anti-mainstream attitudes and styles of dress. With the end of the war in the mid-1970's, and a growing conservative trend in American society, the counterculture movement died.