This is a list of American citizens who have held titles of nobility from other countries. Nobility is not granted by the United States itself under the Title of Nobility Clause of the Constitution.
Prince/Princess[edit]
- Ariana Austin Makonnen, by marriage (Ethiopian Empire)
- Sarah Culberson, by birth (Sierra Leone)
- Josiah Harlan, Prince of Ghor, ennobled (Emirate of Afghanistan)
- Alice Heine, Princess of Monaco, by marriage (Monaco)
- Paul Ilyinsky, by birth (Russia)
- Grace Kelly, Princess of Monaco, by marriage (Monaco)
- Lee Radziwill, by marriage (Holy Roman Empire)
- May Stewart, Princess Anastasia of Greece and Denmark, by marriage (Kingdom of Greece)
Duke/Duchess[edit]
- Nicholas Frederic Brady and Genevieve Brady, ennobled (Holy See)
- Anna Gould, by marriage (Prussia)
- Sacha Hamilton, Duchess of Abercorn, by marriage (United Kingdom)
- Wallis Simpson, Duchess of Windsor, by marriage (United Kingdom)
- Consuelo Vanderbilt, Duchess of Marlborough, by marriage (United Kingdom)
- Meghan Windsor (Markle), Princess Harry, Duchess of Sussex, by marriage (United Kingdom)
Marquis/Marquise[edit]
- Elizabeth Beers-Curtis, by marriage (Second French Empire)
- Grace Curzon, Marchioness Curzon of Kedleston, by marriage (United Kingdom)
- Henry Hathaway, by birth as Henri Léopold, Marquis de Fiennes (Kingdom of Belgium)
- Francis Augustus MacNutt, ennobled (Holy See)
- Medora de Vallombrosa, Marquise de Morès, by marriage (Kingdom of Sardinia)
- Marianne Wellesley, Marchioness Wellesley, by marriage (United Kingdom)
Count/Countess[edit]
- Ethel Beatty, by marriage (United Kingdom)
- Adele Capell, Countess of Essex, by marriage (United Kingdom)
- Clara Longworth de Chambrun, by marriage (Second French Empire)
- Elise, Countess of Edla, by marriage (Kingdom of Portugal)
- Mildred, Countess of Gosford, by marriage (United Kingdom)
- Flora Curzon, Lady Howe, by marriage (United Kingdom)
- Rose Kennedy, ennobled (Holy See)
- Helena Keith-Falconer, Countess of Kintore, by marriage (formerly Duchess of Manchester) (United Kingdom)
- Richard Alan Montagu-Stuart-Wortley, 5th Earl of Wharncliffe, by birth
- Cissy Patterson, by marriage (Austria-Hungary)
- Katherine E. Price, ennobled (Holy See)
- Gladys Vanderbilt Széchenyi, by marriage (Austria-Hungary)
- Alice Cornelia Thaw, by marriage (United Kingdom)
- Benjamin Thompson, ennobled (Holy Roman Empire)
Viscount/Viscountess[edit]
- Waldorf Astor, 2nd Viscount Astor, by birth
- William Waldorf Astor, 1st Viscount Astor, ennobled
- Tennessee Claflin, by marriage (Kingdom of Portugal)
- Thelma Furness, Viscountess Furness, by marriage (United Kingdom)
- Julie Montagu, Viscountess Hinchingbrooke, by marriage (United Kingdom)
Baron/Baroness[edit]
- John Jacob Astor, 1st Baron Astor of Hever, ennobled (United Kingdom)
- John Copley, 1st Baron Lyndhurst, ennobled (United Kingdom)
- Helen Beresford, Baroness Decies, by marriage (United Kingdom)
- Urban Huttleston Broughton, 1st Baron Fairhaven, ennobled (United Kingdom)
- Mary Curzon, Baroness Curzon of Kedleston, by marriage (United Kingdom)
- Elizabeth Wharton Drexel, by marriage (United Kingdom)
- Albert Fairfax, 12th Lord Fairfax of Cameron, by birth (United Kingdom)
- Bryan Fairfax, 8th Lord Fairfax of Cameron, by birth (United Kingdom)
- Charles Fairfax, 10th Lord Fairfax of Cameron, by birth (United Kingdom)
- John Fairfax, 11th Lord Fairfax of Cameron, by birth (United Kingdom)
- Thomas Fairfax, 9th Lord Fairfax of Cameron, by birth (United Kingdom)
- Christopher Guest, 5th Baron Haden-Guest, by birth (United Kingdom)
- Thomas Shaughnessy, 1st Baron Shaughnessy, ennobled (United Kingdom)
- Joanna Shields, Baroness Shields, ennobled (United Kingdom)
- Van Watervliet family, by birth and marriage (Republic of the Seven United Netherlands)
Hereditary Knight[edit]
- Sir James Michael Dunbar, 14th Baronet Dunbar, by birth (United Kingdom)
- Monica von Neumann, by marriage (Austria-Hungary)
Lord/Lady (Untitled)[edit]
- Lady Randolph Churchill, by marriage (United Kingdom)
- Pauline Payne Whitney, by marriage (United Kingdom)
- May Yohé, by marriage (United Kingdom)