Viscount Astor, of Hever Castle in the County of Kent, is a title in the Peerage of the United Kingdom. It was created in 1917 for the financier and statesman William Waldorf Astor, 1st Baron Astor. He had already been created Baron Astor, of Hever Castle in the County of Kent, in 1916, also in the Peerage of the United Kingdom. His eldest son, the second Viscount, was the husband of Nancy Astor, Viscountess Astor, the first woman to sit in the House of Commons. As of 2009 the titles are held by their grandson, the fourth Viscount, who succeeded his father in 1966. He is one of the ninety-two elected hereditary peers that remain in the House of Lords after the passing of the House of Lords Act 1999, and sits as a Conservative.
John Jacob Astor, 1st Baron Astor of Hever, was the second son of the first Viscount. This peerage (created 1956) was a separate creation and not to be confused with the Viscount's subsidiary title of Baron Astor, of Hever Castle in the County of Kent.
Viscounts Astor (1917)
- William Waldorf Astor, 1st Viscount Astor (1848–1919)
- Waldorf Astor, 2nd Viscount Astor (1879–1952)
- William Waldorf Astor, 3rd Viscount Astor (1907–1966)
- William Waldorf Astor, 4th Viscount Astor (b. 1951)
The heir apparent is the present holder's eldest son, the Hon. William Waldorf Astor (b. 1979).
His heir apparent is his son, William Waldorf Astor (b. 2012).