Joanna Marie Valentina "Zizi" Lambrino (3 October 1898 – 11 March 1953) was the first wife of the later King Carol II of Romania.

Easterman would later write that "Carol fell violently in love and was at no pains to dissemble it", despite the obvious disapproval of the royal court for his bestowing his affections on a commoner.

Some say their union was opposed by his parents, but Carol "smuggled" her across the former Russian frontier and they were officially married in the Orthodox Cathedral of Odesa, Ukraine, on 31 August 1918,[which calendar?]

He next married Jeanne Williams (1960–1977); they had one son, Ion Nicolas George Alexander Hohenzollern (born 1961 in Dorset, England).

This places a shadow over the status of Carol II's son, the de facto King of Romania Michael, because if Carol's marriage to Zizi Lambrino was never properly ended, that could invalidate his later royal marriage to Helen of Greece and Denmark, Michael's mother.

ChivalricOrders.org sees this shadow as very slight: "The legality of the annulment of the marriage was not only unchallenged at the time, but significantly, after eventually becoming King, Carol II did not attempt to undo this act nor declare his son Mircea legitimate.