Byzantine empress and, in 1067 and 1071, regent, who has been called the wisest woman of her time.

The daughter of John Macrembolites and niece of Michael Cerularius, the patriarch of Constantinople, Eudocia was the wife of the emperor Constantine X Ducas. After his death in May 1067, she became regent for her three sons—Michael, Andronicus, and Constantine—ruling wisely and moderately and personally taking charge of the education of the heir apparent, Michael (the future Michael VII Ducas).

The threat of the Seljuq Turks, however, necessitated a strong military government, and Eudocia was persuaded to marry Romanus Diogenes, a Cappadocian general, who became the emperor Romanus IV Diogenes in 1068. After his disastrous defeat and capture by the Turks at Manzikert, Armenia, in August 1071, Eudocia and Michael ruled jointly. When Romanus, who had been ransomed from the Turks, attempted to reassert his claim to the throne, he was deposed. Eudocia was soon succeeded by Michael and subsequently entered a convent.