Robert Harley, 1st Earl of Oxford and Earl Mortimer KG (5 December 1661 – 21 May 1724) was a British politician and statesman of the late Stuart and early Georgian periods.

He begins his career as a Whig, before defecting to a new Tory Ministry.

Between 1711 and 1714 he serves as First Lord of the Treasury, effectively Queen Anne's chief minister.

He has been called a Prime Minister, though it is generally accepted that the position is first held by Sir Robert Walpole in 1721.

Harley's government agrees to the Treaty of Utrecht with France in 1713, bringing an end to twelve years of British involvement in the War of the Spanish Succession.

In 1714, he falls from favor following the accession of the first monarch of the House of Hanover, George I, and is for a time imprisoned in the Tower of London by his political enemies.

He is also a noted literary figure and serves as a patron of both the October Club and the Scriblerus Club.

Harley Street is sometimes said to be named after him, although it is his son Edward Harley who actually develops the area.