Eudokia Megale Komnene (died after 4 September 1395), was a Trapezuntine noblewoman, and a member of the powerful Byzantine Komnenos dynasty as a daughter of Emperor Alexios III of Trebizond. She was styled Despoina in Sinop after her first marriage to Muslim Turkmen Tadjeddin Pasha of Sinop, Emir of Limnia, which had been arranged by her father to foster peaceful relations between the Pontic Greek Christians and the neighbouring Muslims.
Eudokia was born on an unknown date, the second daughter of Emperor Alexios III and Theodora Kantakouzene. She had two brothers, and three sisters; the eldest Anna later became Queen consort of Georgia as the second wife of King Bagrat V.
The Chronicle of Michael Panaretos records the marriage on "8 October 1378 at Oinaion of Eudokia and Muslim Turkmen ruler Tadjeddin Pasha of Sinop, Emir of Limnia" after which "the Emperor took over Limnia". Her sisters, Maria and another whose name has not come down to us also married Muslims, but "in this case the bridegroom ... was by far the best." According to Elizabeth Zachariadou, Tadjeddin was not prince of Limnia, but of Niksar, where the tomb of Melik Danishmend is located, and whose territory comprised the fertile plain of Phanaroia, and important fortresses such as Iskefser and Sonusa.
Tadjeddin had sent an envoy to Alexios, who met with the Emperor June 1362 to discuss a marriage, but popular sentiment was against a possible marriage at the time. Such an arrangement was not unprecedented. Prior to Eudokia's wedding, at least two of Alexios' sisters had been married to neighboring Muslim rulers: Maria had been married to Fahreddin Kutlug beg, Emir of Aq Qoyunlu in 1352, while Theodora became the wife of Hajji 'Umar, Emir of Chalybia in 1358.