The Clan Buchan Association website states that Clan Buchan has no official septs, but the following surnames have been identified with the Buchan region in the north-east of Scotland:

Basken, Baskin, Bede, Bichan, Bichen, Bonnieville, Boyne, Buck, Buckie, Bucky, Cawsell, Chapp, Chrystal, Clapperton, Coscrach, Costie, Costy, Cranach, Crannach, Cruddon, Cruden, Crudon, Crystal, Crystal, Crystall, Fitchie, Fitchy, Gammerie, Gammery, Hardin, Hardman/ Hardnan, Kermack, Leisk, Mac, Meason, Merson, Mondie, Mondy, Mundie, Mundy, Nible, Niblo, Ogston, Ogstone, Ogstoun, Prince, Ratcliff, Ratliff, Rattcliff, Rattliff, Runcie, Runcy, Shakle, Tarves, Tarvis, Teunion, Teunon, Tewnion, Tinnon, Tucks, Wadsworth, Wadsworther, West, Whammond, Whyman, Whymon, and Willgook