Kool-Aid Drinker is a pejorative term originating in 1978. It is most often used as a political or personal put-down to describe someone who blindly adheres to a set of beliefs or political system, or who follows an authoritative figure without question. The term is derived from the 1978 mass suicide in Jonestown, Guyana in which Peoples Temple Church leader Jim Jones convinced his followers to commit suicide by drinking grape Flavor Aid (a Kool-Aid type of drink) laced with cyanide. Most of them did so, and as a result over 900 people died.

This term is often used by media personalities, such as the Fox News Channel's Bill O'Reilly and Sean Hannity, to describe individuals with unrelenting political views of one extreme or the other, generally targeting views that oppose their own.

Pejorative political terms