Billennium may refer to:
2nd millennium, the second period of one thousand years in the Common Era 3rd millennium, the period of time which began with the year 2001 Beretta 92 Billennium, a type of pistol Unix billennium, a point in Unix time which occurred in 2001 "Billennium" (short story), a short story by J. G. Ballard
See also Biennial (disambiguation)