The title of Earl of Onslow was created in the Peerage of the United Kingdom in 1801.

Lord Onslow bears the subsidiary titles of Viscount Cranley, of Cranley in the County of Surrey (1801), in the Peerage of the UK, and Baron Onslow, of Onslow in the County of Shropshire and of Clandon in the County of Surrey (1716), and Baron Cranley, of Imber Court in the County of Surrey (1776), in the Peerage of Great Britain. He is also twice (1660, 1674) an English baronet.

The 7th and current Earl is the only hereditary peer to have appeared as a panellist on Have I Got News For You.

The family seat is Clandon House in Surrey.

Barons Onslow (1716)

• Richard Onslow, 1st Baron Onslow (1654-1717)
• Thomas Onslow, 2nd Baron Onslow (1679-1740)
• Richard Onslow, 3rd Baron Onslow (1715-1776)
• George Onslow, 4th Baron Onslow (1731-1814) (became Earl of Onslow in 1801)

Earls of Onslow (1801)

• George Onslow, 1st Earl of Onslow (1731-1814)
• Thomas Onslow, 2nd Earl of Onslow (1754-1827)
• Arthur George Onslow, 3rd Earl of Onslow (1777-1870)
• William Hillier Onslow, 4th Earl of Onslow (1853-1911)
• Richard William Alan Onslow, 5th Earl of Onslow (1876-1945)
• William Arthur Bampfylde Onslow, 6th Earl of Onslow (1913-1971)
• Michael William Coplestone Onslow, 7th Earl of Onslow (b. 1938)