Sir Percy Florence Shelley, 3rd Baronet of Castle Goring (12 November 1819 – 5 December 1889) was the son and only surviving child of Percy Bysshe Shelley and his second wife, Mary Wollstonecraft Shelley. He was thus the only grandchild of Mary Wollstonecraft to live beyond infancy. His middle name, possibly suggested by his father's friend Sophia Stacey, came because he was born in Florence. He had two elder half-siblings, by his father's first marriage, to Harriet Westbrook.
His parents lived in Italy for several years, until his father drowned off Livorno, whereupon his mother moved back to England with him, her only surviving child, in 1822. He joined Harrow School in 1832, and went up to Trinity College, Cambridge in October 1837.
Shelley inherited the baronetcy upon the death of his grandfather in 1844, becoming the 3rd Baronet, of Castle Goring, Sussex. He married Jane Gibson on 22 June 1848, who had previously been married to the Hon. Charles Robert St. John, son of the 3rd Viscount Bolingbroke and the Viscountess Bolingbroke, Baroness Hompesch.
The couple had no children, although they adopted Bessie Florence Gibson, the daughter of Edward Gibson who was possibly Jane Gibson's brother. Bessie Gibson married Lieutenant-Colonel Leopold James Yorke Campbell Scarlett, and was the mother of Shelley, Robert and Hugh Scarlett, the 5th, 6th and 7th Barons Abinger respectively.