Born Diana Dalziel in Paris, France at 5 avenue du Bois-de-Boulogne (Avenue Foch since World War I). Vreeland was the eldest daughter of her American socialite mother, Emily Key Hoffman (1876–1928) and British stockbroker father Frederick Young Dalziel (1868–1960). Hoffman was a descendant of George Washington's brother as well as a cousin of Francis Scott Key. She also was a distant cousin of writer and socialite Pauline de Rothschild (née Potter; 1908–1976). Vreeland had one sister, Alexandra (1907–1999), who later married Sir Alexander Davenport Kinloch, 12th Baronet (1902–1982). Their daughter Emily Lucy Kinloch married Lt. -Col. Hon. Hugh Waldorf Astor (1920–1999), the second son of John Jacob Astor, 1st Baron Astor of Hever and Violet Astor, Baroness Astor of Hever.