Duke Egilmar of Oldenburg (14 October 1934 – 10 May 2013)
Duke Friedrich August of Oldenburg (11 January 1936 – 9 July 2017); married first Princess Marie Cécile of Prussia, had issue, second Donata Countess of Castell-Rüdenhausen, no issue
Duchess Altburg of Oldenburg (b. 14 October 1938); married Baron Rüdiger of Erffa, had issue
Duke Huno of Oldenburg (b. 3 January 1940); married Countess Felicitas-Anita of Schwerin von Krosigk, had two daughters including Beatrix von Storch
Duke Johann of Oldenburg (b. 3 January 1940); married Ilka Gräfin zu Ortenburg, had issue. His daughter Eilika married Archduke Georg of Austria
^C. Arnold McNaughton, The Book of Kings: A Royal Genealogy, in 3 volumes (London, U.K.: Garnstone Press, 1973), volume 1, page 206. Hereinafter cited as The Book of Kings.
The Royal House of Stuart, London, 1969, 1971, 1976, Addington, A. C., Reference: II 277, 349
Princess Helena of Waldeck and Pyrmont (1899–1948)
The generations are numbered from the ascension of Frederick August I as Duke of Oldenburg in 1774 and remain unchanged even when its ruler became Grand Duke. This list is not meant to be comprehensive as it includes only duchesses with articles.