Lady Margaret Erskine (died 5 May 1572) was a mistress of King James V of Scotland.
She was a daughter of John Erskine, 5th Lord Erskine and Lady Margaret Campbell.
James V had a number of mistresses in his time, but some accounts describe her as his favourite. She was the mother of the most important of his illegitimate children, James Stewart, 1st Earl of Moray, who was Regent during the minority of James VI.
In 1527, Margaret married Sir Robert Douglas of Lochleven, who was killed at the Battle of Pinkie Cleugh. Her son Robert Douglas was sent to England and Cambridge University in 1560 as a hostage for the Treaty of Berwick. She was the châtelaine of Lochleven Castle when Mary, Queen of Scots was kept there, with her eldest surviving son William Douglas, 6th Earl of Morton.
Although Margaret Erskine had married Robert Douglas there is evidence that James V may have considered arranging their divorce and marrying his mistress. It seems that James or one of his advisors sought the advice of the Pope in the matter in June 1536. Shortly before James V finalised his marriage contract with Madeleine of Valois in November 1536, Charles, Bishop of Macon and French ambassador at the Vatican, wrote discussing his audience with the Pope. The Bishop had told the Pope that James never intended to marry Margaret and the petition was an imposture. The Pope replied that he had postponed any grant, thinking that the proposal was made without the King's knowledge.
Chronicle accounts and English letters also mention this scheme and the involvement of James Hamilton of Finnart. One of the English ambassador Sir William Howard's informants was Margaret Tudor, and he reported to Henry VIII;
"Sire, I hear, both by the Queen's Grace your sister and diverse others that the marriage is broken between the King's Grace your nephew and the Monsieur de Vendôme, and he will marry a gentlewoman in Scotland, the Lord of Erskine's daughter, who was with your Grace the last summer at Thornbury; by whom he has had a child, having a husband, and his Grace has found means to divorce them. And there is great lamentation made for it in this country as far as men dare. Sire, there was no man made privy to this matter but Sir James Hamilton." (25 April 1536)
Had the marriage gone ahead, their son James Stewart, the future Regent, could have been declared legitimate. By July 1536, the Imperial ambassador in London, Eustace Chapuys, and Spanish diplomats at the Vatican believed the marriage had already taken place.
In the 1570s Margaret Erskine looked after her granddaughters at the New House of Lochleven and kept up a correspondence with their mother, Agnes Keith, Countess of Moray. In January 1570, she wrote that Lochleven Loch was frozen, and her son was in the "Loich", the old castle on the lake island, because he was keeping the Earl of Northumberland, who was a fugitive from the Northern Rebellion. In June 1571, she wrote of her health and complained that Agnes, her daughter-in-law had not visited;
"Ye sall onderstand that I have beyne wery extreme seik baith in my bodye and stomak, and with ane sair leg, quhairoff (I) am nocht throichlie conwelleseit as yett ... I wald skarslie have belevit ye would have bene neir (at) hand and veseit me nocht, and frindis heir."