John Jones "of Ystrad" (15 September 1777 – 10 November 1842), was a Welsh politician, MP for Carmarthen from 1821 to 1832. He was born in King Street, Carmarthen, the son of a solicitor. Educated at Eton College and Christ Church, Oxford, he went on to Lincoln's Inn to qualify as a barrister. His work on the South Wales circuit took him back to his home area, and he stood as a Conservative at the election of 1812. In 1815, he replaced Sir Thomas Picton as MP for Pembroke Boroughs. In 1818 he was again defeated at Carmarthen, but eventually won the seat three years later.