William Waldorf Astor III, 4th Viscount Astor (born 27 December 1951) is an English businessman and politician who sits as a Conservative hereditary Lord Temporal in the House of Lords. He is a member of the prominent Astor family.
Astor was a Lord-in-waiting (a House of Lords whip) from 1990 to 1993. He was then made a Parliamentary Under Secretary of State at the Department of Social Security. In 1994, he moved to the Department of National Heritage where he served until leaving the government in 1995.
He was a member of the Founding Council of the Rothermere American Institute at the University of Oxford.
Viscount Astor is co-founder and former Chairman of Silvergate Media (now Sony Pictures Television Kids) and director of Networkers Plc (since 2007) and trustee of Stanley Spencer Gallery in Cookham.
Astor was an early opponent of the HS2 high-speed rail project.
Astor married Annabel Lucy Veronica Jones (born 1948), daughter of Timothy Angus Jones and Patricia David Pandora Clifford on 14 January 1976. They have three children:
The heir to the viscountcy is his elder son, Will.
His wife Annabel's stepfather was his uncle Michael Langhorne Astor.
Viscountess Astor was previously married to Sir Reginald Sheffield, 8th Baronet by whom she is the mother of Samantha Cameron, wife of former Prime Minister David Cameron.