Earl Spencer is a title in the Peerage of Great Britain that was created on 1 November 1765, along with the title Viscount Althorp, of Althorp in the County of Northampton, for John Spencer, 1st Viscount Spencer. He was a member of the prominent Spencer family and a great-grandson of the 1st Duke of Marlborough. Previously, he had been created Viscount Spencer, of Althorp in the County of Northampton, and Baron Spencer of Althorp, of Althorp in the County of Northampton, on 3 April 1761.