The term "Old Ones" can refer to a number of creatures in the Cthulhu Mythos, including.
- Great Old Ones
- Elder Things as described in At the Mountains of Madness (fiction)
- Star-Spawn of Cthulhu as described in The Call of Cthulhu (fiction)
- Old One (spirit), a race of ghostlike beings that serve Yog-Sothoth. (Used in this sense in H.P. Lovecraft's "The Dunwich Horror (fiction)", and in Cthulhu Dark Ages.)
- The denizens of K'n-yan. (Used in this sense in H.P. Lovecraft's "The Mound (fiction)".)