The Stone Lud is a standing stone in the parish of Bower in Caithness, Highland Scotland, at , Grid ref (or on ), and about six kilometres (four miles) south of Castletown.

The stone has been claimed as the grave stone of Ljot the 10th century earl of Norse Orkney. At about three metres above ground level, however, it seems rather taller than anything the 10th-century Norse are likely to have used. It is one of the more impressive standing stones in Caithness and has mass and size to compare with those of the Ring of Brodgar in Orkney. Also it is one of two stones of which the second is now fallen, about 30 metres from the first. When erect the second is supposed to have been behind the first as seen from the direction of the northern hemisphere summer solstice sunset.

In The Standing Stones of Caithness (2003) Leslie J Myatt gives the alighnment of the stones as 322 degrees, from the fallen stone to the still standing stone. This alignment may appear to suggest a summer-solstice sunset which is too far north for the latitude. However, at about 75 metres, the altitude of the stones is quite high with respect to a distant sea-level horizon.

The summer-solstice sunset alignment has correspondence with that of Maes Howe, a chambered cairn in Orkney, which is built so that sunlight will penetrate the cairn at the time of the same sunset.

The name of Ljot however is very close to that of Lot or Loth, the mythic King of Orkney & Lothians and Round Table (Arthurian) Knight, and in Celtic Myths and Legends (Gresham 1912, page 359 as republished by Paragon 1998, ISBN 0752526766) Charles Squire identified Lot as a late incarnation of a British god who is remembered in medieval Welsh legend as Lludd .