James Nelthorpe (1675–1734), of Lynford, Norfolk, was a British landowner and Whig politician who sat in the House of Commons from 1728 to 1734. Nelthorpe was baptized on 17 November 1675, the son of Edward Nelthorpe of St. Mary Abchurch, London and his wife Mary. He was educated at Merchant Taylors School in 1687. In 1717 he acquired the manor of Lynford from Sir Charles Turner, 1st Baronet where he built Lynford Hall. Sir Robert Walpole often spent a night there on his way to Houghton.