Euphemia Elphinstone (also written Euphame or Eupheme; 11 May 1509 – either 1542 or after 1547) was a mistress of James V of Scotland and the mother of his son Robert Stewart, 1st Earl of Orkney, born in 1532, as well as another royal bastard who died in childhood. One of her sons with her husband John Bruce was Laurence Bruce of Cultmalindie (1547–1617), the builder of Muness Castle.
She was the second daughter of Alexander Elphinstone (born c. 1480, died 9 September 1513, at the Battle of Flodden), created Lord Elphinstone in 1510, and Elizabeth Barlow (Berclay) of Aberdeenshire (c. 1476 – 10 September 1518). The family hailed from Elphinstone in Stirling. Her brother Alexander, Lord Elphinstone, died at Edinburgh following the Battle of Pinkie Cleugh, and is the ancestor of the Elphinstone family. Euphemia married John Bruce of Cultmalindie (c. 1507 – March 1546/7), a descendant of Robert the Bruce, and had five children: Laurence Bruce, Robert Bruce (born c. 1536), Henry Bruce (born c. 1538), James Bruce (born c. 1540) and Euphamie Bruce (born c. 1542). She died either in 1542, or after 1547: there is no firm evidence for any death date.
Euphemia appears to have been, in her own right, rather unimportant: the daughter of a minor noble, she married a minor member of the Bruce family, and many consider her to be only a passing fancy to James V (although if she conceived by him on two separate occasions then this would appear slightly misleading). However, her children and descendants were to be important in the history of the Shetland Islands and Orkney Islands. Her two most significant children, Laurence Bruce and Robert Stewart and their families were to become closely entwined in the Shetland Islands, of which Laurence Bruce was appointed Sheriff by his half-brother.
According to legend, many people in the Shetland Islands are descended from her; in particular, those named Bruce are supposed to be descended from her children by John Bruce.
Another descendent of hers is the Archbishop of Canterbury, Justin Welby.