The title of Earl of Harrowby was created in the Peerage of the United Kingdom in 1809.

The Earl bears the subsidiary titles of Viscount Sandon (1809) in the Peerage of the UK and Baron Harrowby (1776) in the Peerage of Great Britain.

Barons Harrowby (1776)

• Nathaniel Ryder, 1st Baron Harrowby (1735-1803)
• Dudley Ryder, 2nd Baron Harrowby (1762-1847) (became Earl of Harrowby in 1809)

Earls of Harrowby (1809)

• Dudley Ryder, 1st Earl of Harrowby (1762-1847)
• Dudley Ryder, 2nd Earl of Harrowby (1798-1882)
• Dudley Francis Stuart Ryder, 3rd Earl of Harrowby (1831-1900)
• Henry Dudley Ryder, 4th Earl of Harrowby (1836-1900)
• John Herbert Dudley Ryder, 5th Earl of Harrowby (1864-1956)
• Dudley Ryder, 6th Earl of Harrowby (1892-1987)
• Dudley Danvers Granville Coutts Ryder, 7th Earl of Harrowby (b. 1922)