Fiver may be:

  • A common slang term for:
    • An Australian five-dollar note
    • A British five-pound note
    • A five-euro note
    • A United States five-dollar bill
  • A fifth columnist or saboteur, in wartime slang
  • A large forehead, generally the height of five fingers placed horizontally on the forehead.
  • Fiver (racing), a Swedish endurance racing team
  • 5*, a UK TV channel operated by Channel 5 formerly known as Fiver
  • Fiver (puzzle), a math game played on a 5x5 grid, distantly related to Conway's Game of Life
  • Fiver (Watership Down), a fictional rabbit in the Richard Adams novel Watership Down
  • The Fiver, a humorous daily football email by The Guardian newspaper
  • Fiverr, a global online marketplace for buying and seling services starting at $5
  • Zaidiyyah Shi'a Muslims, who disagree with the majority of Shi'a on the identity of the Fifth Imam