Randal Arthur Henry Plunkett, 19th Baron of Dunsany (25 August 1906 – 8 February 1999) was an Irish peer. He was the son of the famous author and playwright Edward Plunkett, 18th Baron of Dunsany and Lady Beatrice Child Villiers, daughter of Victor Child Villiers, 7th Earl of Jersey.
The family seat of the Lords Dunsany is at Dunsany Castle, Dunsany, Co. Meath, Ireland. The original Dunsany and nearby Killeen Castles were built by Geoffrey de Cusack who was a tenant of Sir Hugh de Lacy, an early Cambro-Norman who arrived in Ireland with Strongbow, sometime between his arrival in Ireland in 1172 and the year 1181. Sir Hugh was given most of County Meath. The Plunketts of Dunsany and Killeen are descended from Geoffrey de Cusack and Matilda (née le Petit sister of William le Petit of Dunboyne Castle). The castle was built on an area of land believed to have been the site of an earlier Dún or fort, which may give its name to the locality. Both castles came to the Plunkett family through the marriage in the early 15th century of Sir Christopher Plunkett (Deputy Governor of Ireland in 1432) to Lady Joan de Cusack. It is claimed that the castle is the longest occupied home and one of the oldest surviving continuously inhabited buildings in Ireland.
Randal Plunkett was born on 25 August 1906 and was educated at Eton College, Eton, Berkshire, England. He fought in the North-West Frontier in 1930 in the Guides Cavalry regiment of the British Indian Army, and was promoted to the rank of Lieutenant-Colonel. He also fought in the Second World War and retired from Military Service in 1947 having been decorated (Medal and Clasp). In 1957 he succeeded to the family title on the death of his father the 18th Lord Dunsany.