Trekkie (or Trekker) is a term used to describe a fan of all or part of the Star Trek fictional universe.

Some Star Trek enthusiasts prefer the term "Trekkie", while some others self-identify as "Trekker". Self-identification as a "Trekkie" became even less popular after a famous national television parody in 1986 (see Parodies below); several self-described "Trekkers" were quoted as saying they "had a life" (contrasting themselves from "Trekkies").