Eudokia Baïana (died 12 April 901) was the third wife of Leo VI the Wise.
The work Theophanes Continuatus was a continuation of the chronicle of Theophanes the Confessor by other writers, active during the reign of Constantine VII. The work records the few details known about her.
According to Theophanes, Eudokia came from the Opsician Theme. The Opsician Theme was originally composed of all of Bithynia and Paphlagonia, stretching from Abydos on the Dardanelles to Sinope on the Black Sea and inland to Ancyra. In the 20th century, the lands once belonging to the Theme form most of the northwestern quarter of Asiatic Turkey.
In Spring, 900, Leo VI married Eudokia. His previous two wives had predeceased him. De Ceremoniis by Constantine VII names as many as three daughters born of the previous marriages but no son. Leo wanted to secure his succession by this marriage. George Alexandrovič Ostrogorsky points that a third marriage was technically illegal under Byzantine law and against the practices of the Eastern Orthodox Church at the time. Leo VI had to seek permission by Ecumenical Patriarch Antony II of Constantinople.
A year later Eudokia died while giving birth. Theophanes considers the son stillborn and unnamed. However "De Ceremoniis" while listing the children of Leo VI names a son called Basil, which might indicate her son survived long enough to be named. "De Ceremoniis" gives her burial place as the Church of the Holy Apostles in Constantinople.