Greg King (born 1964) is an American author, best known for his biographies of prominent historical figures.
Born in 1964, King first became interested in history at the age of twelve, after watching two films about Imperial Russia's last royal family, the Romanovs: Nicholas and Alexandra (1971), and Anastasia (1956), which after which he started reading all the books he could find on the subject, including Robert K. Massie's 1967 book, Nicholas and Alexandra.
- The Last Empress: The Life and Times of Alexandra Feodorovna, Empress of Russia, 1996
- The Mad King: The Life and Times of Ludwig II of Bavaria, 1996
- The Man Who Killed Rasputin: Prince Felix Youssoupov and the Murder That Helped Bring Down the Russian Empire, 1996
- The Duchess of Windsor: The Uncommon Life of Wallis Simpson, 1999
- Sharon Tate and the Manson murders, 2000
- The Fate of the Romanovs, co-authored with Penny Wilson, 2003
- The Court of the Last Tsar: Pomp, Power and Pageantry in the Reign of Nicholas II, 2006
- Gilded Prism: The Konstantinovichi Grand Dukes & the Last Years of the Romanov Dynasty, with Penny Wilson, 2006
- Twilight of Splendor: The Court of Queen Victoria During Her Diamond Jubilee Year, 2007
- A Season of Splendor: The Court of Mrs Astor in Gilded Age New York, 2008
- The Resurrection of the Romanovs: Anastasia, Anna Anderson, and the World's Greatest Royal Mystery, with Penny Wilson, 2010
- The Assassination of the Archduke: Sarajevo 1914 and the Romance That Changed the World, with Sue Woolmans, St. Martin's Press, 2013
- Lusitania: Triumph, Tragedy, and the End of the Edwardian Age, with Penny Wilson, St. Martin's Press, 2015