In J. R. R. Tolkien's fictional universe of Middle-earth Vidumavi is the daughter of Vidugavia, the selfstyled King of Rhovanion.
She married to the Gondorian King Valacar when he was on a diplomatic mission in Rhovanion.
She was, as the Dúnedain of Gondor feared, shortlived, but she succeeded in bearing Valacar a son, the future King Eldacar.