Rupert Charles William Bullard Onslow, 8th Earl of Onslow (born 16 June 1967) is a British noble and hereditary peer.
The son of the late Michael Onslow, 7th Earl of Onslow and Robin, Countess of Onslow. Rupert Onslow, 8th Earl of Onslow was educated at Eton College, Western Kentucky University and at King's College London where he graduated with a Bachelor of Arts degree in 1990. Lord Onslow owns and manages the agricultural Estate Clandon Park, the Seat of the Earls of Onslow in Surrey, is a Director of Clandon Park Ltd & also specialises in insuring fine art and is the Fine Art Underwriter at The Channel Syndicate in Lloyd's.
Rupert Onslow, then Viscount Cranley married Leigh Jones-Fenleigh, then Viscountess Cranley on 10 September 1999, who attended Cheltenham Ladies' College. She became the Countess of Onslow when the 8th Earl of Onslow inherited his fathers title. They have one child Lady Olympia Patricia May-Rose Onslow (born 7 July 2003)
Rupert Onslow, 8th Earl of Onslow inherited the Earldom on the death of his father Michael Onslow, 7th Earl of Onslow in 2011.