John Komnenos Angelos Doukas Synadenos (Greek: Ἰωάννης Κομνηνός Ἄγγελος Δούκας Συναδηνός) was a Byzantine noble and military leader with the rank of megas stratopedarches during the reigns of Michael VIII Palaiologos (r. 1259–1282) and Andronikos II Palaiologos (r. 1282–1328).
Synadenos appears in 1276/1277, when, along with the megas konostaulos Michael Kaballarios, he led an army against the independent ruler of Thessaly, John I Doukas.
The Byzantine army was routed at the Battle of Pharsalus, and Synadenos himself was captured, while Kaballarios was killed whilst trying to escape.
[1][2][3] He was released or ransomed from captivity, and in 1281 he participated in the campaign against the Angevins in Albania which led to the Byzantine victory at Berat.
After his death (sometime between 1310 and 1328), his wife, Theodora Palaiologina, the daughter of Constantine Palaiologos, the half-brother of Michael VIII, became a nun with the name Theodoule, and founded the Convent of the Mother of God Bebaia Elpis ("Certain Hope") in Constantinople.