Dau of Alexander Erskine (d. 1756), 5th Earl of Kellie, and Janet Pitcairn (d. 1775). Sister of Elizabeth, Anne, Archibald, Andrew and Thomas Alexander Erskine. Married (1763) to Sir Robert Anstruther (1733-1818), 3rd Bart of Balcaskie. She was the only one of the six children of the 5th Earl of Kellie who had any descendants. She had 6 children with Anstruther, but died just 10 days after the birth of the sixth, Phillip, on October 14 , 1770.
Boswell described her as having the "most lovely looks and great vivacity" during his stay at Kellie from October 30 to November 3, 1762.