Joasaph (Greek: Ιωάσαφ; Russian: Иоасаф) is a masculine given name. Joasaph is another name for Josaphat, the legendary martyred prince in the story of Barlaam and Josaphat; according to E. A. Wallis Budge, this name Joasaph ultimately originated as a mistranslation of Bodhisattva. The Ethiopic form of the name is Yewasef. People with this name include:
John VI Kantakouzenos (1292–1382), Byzantine emperor from 1347 to 1354, assumed the name Joasaph Christodoulos after his retirement to a monasteryJoasaph I of Constantinople (fl. 1460s), Ecumenical Patriarch of ConstantinopleJoasaphus, Metropolitan of Moscow (died 1556), Metropolitan of Moscow from 1539 to 1542Joasaph II of Constantinople (fl. 1550s–1560s), Ecumenical Patriarch of ConstantinopleJoasaph of Belgorod (1705–1754), bishop of BelgorodJoasaph Bolotov (1760–1799), Russian Orthodox missionary in AlaskaJoasaph (McLellan) (1962–2009), Head of the Russian Ecclesiastical Mission in Jerusalem of the Russian Orthodox Church Outside Russia