Danneskiold-Samsøe is a Danish family of high nobility, formerly holding the island of Samsø as a fief. The family uses a traditional spelling of the name; a modern spelling would be Danneskjold-Samsø.
The name was created for several descendants of Danish monarchs of the House of Oldenburg, born of their liaisons with royal mistresses. The first grantees were children from the 1677 marriage between Countess Antoinette of Aldenburg and Ulrik Frederik Gyldenløve, Count of Laurvig, a celebrated (Norwegian) general and the son of Frederick III of Denmark by his mistress Margrethe Pape, King Christian V, the count's half-brother, granted a comital title to all of his male-line descendants.
The next grantees were all the children of Christian Gyldenløve, Count of Samsø, the eldest son of Christian V by his mistress Sophie Amalie Moth in 1696. He married his cousin, Countess Antoinette Augusta of Aldenburg (1660-1701) (eldest daughter of Count Anton I of Aldenburg and Knyphausen and his first wife, Countess Auguste Johanna zu Sayn-Wittgenstein-Hohenstein, himself a legitimated son of Anton Gunther, last independent Count of Oldenburg). The male Danneskiold-Laurvigen line was extinguished in 1783, and the Laurvig countship was inherited through an heiress by the noble Danish Ahlefeldt family. In 1786, François Xavier Joseph Gyldenløve, second Count of Løvendal, great-grandson of Count Ulrik Frederik's first marriage, was granted the surname Danneskiold as well ; but this Danneskiold-Løvendal branch, too, was extinguished in its male line upon the death of his childless son in 1829. The first marriage of Count Christian produced only daughters, but the issue of his second marriage succeeded to the countship of Samsø and continues in male line, bearing the surname "af Danneskiold-Samsøe".
All Danneskiolds since 1829 have been descendants of the eldest son of Christian V and his mistress Sofie Amalie Moth (1654-1719), whom the king elevated to be the first Lensgrevinde til Samsø ("Countess of Samsø"). A descendant, Countess Frederikke Louise af Danneskiold-Samsøe (1699-1744,) married her kinsman Christian August, Duke of Schleswig-Holstein-Sonderburg-Augustenburg (1696-1754), a partitioned-off duke, and from whose marriage all the future Augustenborgs descend.
The present comital family numbers the noble families Ahlefeldt, Frijs-Frijsenborg, Kaas, Trolle, Ulfeldt, Huitfeldt, Sehested, Gyldenstierne, Rosenkrantz, Rantzau, Reventlow, Brahe, Grubbe, Krag til Juellund, and Krag-Juel-Vind-Frijs among their ancestress-linked relatives.