Robert Smythson (1535 – 15 October 1614) was an English architect. Smythson designed a number of notable houses during the Elizabethan era. Little is known about his birth and upbringing—his first mention in historical records comes in 1556, when he was stonemason for the house at Longleat, built by Sir John Thynne (ca. 1512–1580). He later designed Hardwick Hall, Wollaton Hall, Burton Agnes Hall, and other significant projects. Historically, a number of other Elizabethan houses, such as Gawthorpe Hall and Chastleton House, have been attributed to him on stylistic grounds.