John Leslie-Melville, 9th Earl of Leven

John Thornton Leslie-Melville, 9th Earl of Leven, 8th Earl of Melville DL JP (18 December 1786 – 16 September 1876) was a Scottish peer and soldier.

Early life John Thornton was born on 18 December 1786. He was the son of Alexander Leslie-Melville, 7th Earl of Leven and the former Jane Thornton (1757–1818). His siblings included the Hon. William Leslie-Melville, the Hon. and Rev. Robert Leslie-Melville, the Hon. Alexander Leslie-Melville of Branston Hall, Lady Lucy Leslie-Melville (wife of Henry Smith), Lady Jane Leslie-Melville (wife of Francis Pym), and Lady Marianne Leslie-Melville (wife of Abel Smith). The Earldom of Melville has been held by the Earls of Leven since 20 May 1707.

He was Deputy Paymaster to the Forces in the Peninsula in 1809; he was a founding partner in the banking partnership Williams, Deacon, Labouchere, Thornton & Co; he was a Representative Peer for Scotland (Conservative) from 1865 to 1876. Lady Florence Lucy Leslie-Melville (1848–1930) Lady Kathleen Mabel Leslie-Melville (d. 1958), who married Charles Henry Farrer, a grandson of Thomas Fremantle, 1st Baron Cottesloe, in 1894.

Lord Leven died on 16 September 1876 and was succeeded in the earldoms by his eldest surviving son, Alexander. He is buried with his second wife Sophia on the south side of the southern roundel in Brompton Cemetery in London.