Robert Vernon Atherton Gwillym (c.1741–1783) was a British country landowner and politician who sat in the House of Commons from 1774 to 1780. Gwillym was the second son of Robert Gwillym of Langstone, Herefordshire and his wife Elizabeth Atherton (1721-1763), daughter of Richard Atherton (1700-1726) and Elizabeth Farrington of Atherton Hall. He is a direct descendant of Richard Atherton. He married Henrietta Maria Legh, daughter of Peter Legh (1706–1792] of Lyme Park and Bank Hall in January 1763. In 1766 at the age of 25, both he and his family were painted by Joseph Wright of Derby