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 William Waldorf Astor, who had previously been created Baron Astor, of Hever Castle in the County of Kent. The titles remain united. The 1st Viscount's second son was created Baron Astor of Hever in 1956.

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)