Elizabeth Lamb, Viscountess Melbourne was one of the most influential of the political hostesses of the extended Regency period, and the wife of Whig politician Peniston Lamb, 1st Viscount Melbourne. She was the mother of William Lamb, 2nd Viscount Melbourne, who became Prime Minister of the United Kingdom, and several other influential children. Lady Melbourne was known for her political influence and her friendships and romantic relationships with other members of the English aristocracy, including Georgiana Cavendish, Duchess of Devonshire, Francis Russell, 5th Duke of Bedford, and George, Prince of Wales. Because of her numerous love affairs, the paternity of several of her children is a matter of dispute.

William Lamb, 2nd Viscount Melbourne was a Whig politician who served as the Home Secretary and twice as the Prime Minister of the United Kingdom. Some sources indicate that his full name was Henry William Lamb.