Old One

Old One, Old Ones, Great Old One or Great Old Ones may refer to:
 * The Great Old Ones, fictional Cthulhu Mythos deities in the works of H. P. Lovecraft
 * The Elder Things, fictional Cthulhu Mythos creatures in the works of H. P. Lovecraft
 * The Great Old Ones (Call of Cthulhu), an adventure supplement for the Call of Cthulhu role-playing game by Chaosium
 * The Old One, a character in The Keys to the Kingdom
 * "The Old One", an episode of Playdate
 * Old Ones (Palladium Books), a 1984 book written by Kevin Siembieda
 * Old Ones (Buffy the Vampire Slayer), fictional demons in Buffy the Vampire Slayer
 * Old Ones, mystical beings in The Dark Is Rising Sequence
 * Old Ones, an ancient race of advanced, god-like aliens in the Warhammer Fantasy setting
 * Old Ones or Elder Bairns, fictional creatures in Blood-C