Henry John Temple, 3rd Viscount Palmerston, KG, GCB, PC (20 October 1784 – 18 October 1865), known popularly as Lord Palmerston, was a British statesman who served twice as Prime Minister in the mid-19th century. Popularly nicknamed "Pam", he was in government office almost continuously from 1807 until his death in 1865, beginning his parliamentary career as a Tory and concluding it as a Liberal.

He is best remembered for his direction of British foreign policy through a period when Britain was at the height of its power, serving terms as both Foreign Secretary and Prime Minister. Some of his aggressive actions, now sometimes termed liberal interventionist, were highly controversial at the time, and remain so today. He was the most recent British Prime Minister to die in office.