The gens Belliena or Billiena was a minor plebeian family at ancient Rome. Bellienus is the form that occurs in writers, while Billienus is more common in inscriptions. Members of this gens are first mentioned toward the end of the Republic. Lucius Bellienus obtained the praetorship in 107 BC, but was prevented from obtaining the consulship. The Bellieni occur in history down to the time of Caesar, after which the family faded into obscurity; but others are known from inscriptions.