John Vesey, 6th Viscount de Vesci

John Eustace Vesey, 6th Viscount de Vesci (25 February 1919 – 13 October 1983), was an Irish peer.

He was the son of Lt. Col. Hon. Thomas Eustace Vesey and Lady Cecily Kathleen Browne, daughter of Valentine Browne, 5th Earl of Kenmare. He became the Viscount de Vesci of Abbey Leix on 16 August 1958. He succeeded his paternal uncle, the 5th Viscount, who was survived by his widow, Lois (daughter of Sir Cecil Edmund Lister-Kaye, 4th Bt., and widow a first time of the 5th Earl of Rosse and mother of the 6th Earl of Rosse). He was the great-grandson of Thomas Vesey, 3rd Viscount de Vesci. His father was an Eton and Oxford-educated Lieutenant Colonel in the Irish Guards who fought and was wounded twice in the First World War. He himself was also in the Irish Guards, fighting in the Second World War and being captured.

He lived at Abbey Leix House on the River Nore in County Laois. In 1967, he sold the De Vesci Collection that was housed at Abbey Leix House to the National Library of Australia. This acquisition added 1648 books (about 2900 volumes) and 54 serials (about 390 volumes) to the National Library of Australia.