Decima can refer to:

  • Decima (mythology), a goddess in Roman mythology and one of the Parcae (Fates)
  • D├ęcima, a type of poetic form with roots in Spanish literature
  • Decima Research, a Canadian polling company
  • Decima gallery, a London-based arts organisation
  • The Latinized name of Deshima island off the Japanese coast, where a unique Dutch trading establishment was located during the empire's isolation