William Pitt the Younger (28 May 1759 – 23 January 1806) is a British politician of the late 18th and early 19th centuries.

He becomes the youngest Prime Minister in 1783 at the age of 24.

He leaves office in 1801, but is Prime Minister again from 1804 until his death in 1806.

He is also the Chancellor of the Exchequer throughout his premiership.

He is known as "the Younger" to distinguish him from his father, William Pitt the Elder, who had previously served as Prime Minister of Great Britain.

In 1766 he gains the style of The Honourable when his father is created an Earl.

The younger Pitt's prime ministerial tenure, which comes during the reign of George III, is dominated by major events in Europe, including the French Revolution and the Napoleonic Wars.

Pitt, although often referred to as a Tory, or "new Tory", calls himself an "independent Whig" and is generally opposed to the development of a strict partisan political system.

He is best known for leading Britain in the great wars against France and Napoleon.

Pitt is an outstanding administrator who works for efficiency and reform, bringing in a new generation of outstanding administrators.

He raises taxes to pay for the great war against France, and cracks down on radicalism.

To meet the threat of Irish support for France, he engineers the Acts of Union 1800 and tries (but fails) to get Catholic Emancipation as part of the Union.

Pitt creates the "new Toryism," which revives the Tory Party and enables it to stay in power for the next quarter-century.