Sir John Johnston, 3rd Baronet of Caskieben (c. 1648 – 23 December 1690) was a Scottish soldier who was executed for his part in the abduction of Mary Wharton.
Johnston was a captain in the army, and served under King William III in Flanders and in Ireland, where he was present at the Battle of the Boyne.
[1][2] In November 1690 Johnston aided his friend Captain James Campbell in the abduction and forced marriage of thirteen-year-old heiress Mary Wharton.
Though Campbell escaped, for his part in the affair Johnston was hanged at Tyburn on 23 December 1690, aged forty-two.
He was unmarried, and was succeeded by his cousin John Johnston of Newplace, a merchant at Aberdeen.