Catherine St Aubyn Molesworth (2 September 1760 – 21 October 1836) was a British amateur artist.
She was the daughter of Sir John St Aubyn, 4th Baronet of Clowance, Cornwall, and his wife, Elizabeth Wingfield.
[2][3] Her brother was the long-serving Member of Parliament and fossil collector Sir John St Aubyn, 5th Baronet.
Her father was a friend and patron of the painter John Opie, and he arranged for Catherine to have lessons.
[4] She married on 26 June 1790 her cousin the Reverend John Molesworth who was the rector of St Breock in Cornwall.