Joseph Marryat (1757–1824) was an English businessman and British member of Parliament for Horsham and later for Sandwich. He was of Huguenot descent.
Marryat, whose father was the medical writer and physician Thomas Marryat, became a West Indian merchant and served as chair of Lloyd’s from 1811 until his death. He lived in Sydenham, Kent, and at Wimbledon House, Surrey.
Marryat's wife was the American Charlotte, née von Geyer, one of the first women admitted to membership of the Royal Horticultural Society, on the strength of her garden at Wimbledon House. She died in 1854. One son, also called Joseph Marryat (1790–1876), was likewise a member of Parliament. A second son, Frederick Marryat, was a novelist and British Royal Navy officer.
Joseph Marryat was an ardent anti-abolitionist, active in parliament and engaging in polemical debate through issuing pamphlets.
In 1819, Marryat joined the London bank of Sir Charles Price, based at 1 Mansion House Street. The bank then became known as Marryat, Kay, Price and Coleman. He died in his office there on 12 January 1824.