thumb|200px|Henry John Temple, 3rd Viscount Palmerston.
Viscount Palmerston was a title in the Peerage of Ireland. The title is derived from Palmerstown in Ireland, which was also known as Palmerston. The name is the origin of several place names in Australia, Canada, New Zealand, and other former British possessions. It was created on 12 March 1723 for Henry Temple, who subsequently represented East Grinstead, Bossiney and Weobley in the British House of Commons. He was made Baron Temple, of Mount Temple in the County of Sligo, at the same time, also in the Peerage of Ireland. He was succeeded by his grandson, the 2nd Viscount, who represented seven constituencies in the House of Commons and served as a Lord of the Admiralty and Lord of the Treasury. On his death the titles passed to his son, the 3rd Viscount, who became a distinguished politician and served three times as Foreign Secretary and twice as Prime Minister of the United Kingdom. At his death in 1865 the 3rd Viscount was granted a state funeral, the fourth non-royal to be given this honour. Lord Palmerston was childless and the barony and viscountcy became extinct on his death.
The Temple family descended from Peter Temple, of Dorset and Marston Boteler. His eldest son John Temple acquired the Stowe estate in Buckinghamshire and founded the English branch of the family from whom the Viscounts Cobham, the Dukes of Buckingham and Chandos and the Earls Temple of Stowe are descended. Peter Temple's younger son Anthony Temple was the founder of the Irish branch of the family from whom the Viscounts Palmerston descended. His son Sir William Temple (1555–1627) was secretary to Sir Philip Sidney and the Earl of Essex and afterwards provost of Trinity College Dublin.
See also
- Viscount Cobham
- Duke of Buckingham and Chandos
- Earl Temple of Stowe
- Baron Mount Temple