Clandon Park is an 18th century Palladian mansion in West Clandon just outside Guildford, Surrey, in the United Kingdom. It has been a National Trust property since 1956.
The house was built, or perhaps thoroughly rebuilt, around 1730–33 (the latter date is on rainwater leads), designed by the Venetian architect Giacomo Leoni, replacing an Elizabethan property which was bought in 1641 by Sir Richard Onslow. The new building was commissioned by his great-grandson Thomas, 2nd Baron Onslow. Many members of the Onslow family followed political careers—three of them, including Arthur Onslow, were Speakers of the House of Commons.