John Palaiologos was a member of the reigning Palaiologos dynasty of the Byzantine Empire, who served as governor of Thessalonica.
He was the son of the general Constantine Palaiologos, in turn a son of Emperor Michael VIII Palaiologos (reigned 1259–1282), and his wife Irene Palaiologina Raoulaina.
In 1305 John received the court rank of panhypersebastos. By 1325/26, at a time of civil war, he was governor of Thessalonica. Andronikos II sought to placate him by sending envoys bearing the insignia of a Caesar, the second-highest title in Byzantine court hierarchy, and John agreed to give up his revolt and return to Thessalonica.
However, he contracted an illness and died soon after at Skopje.
John married a lady named Irene, of unknown family. The couple had a daughter, Maria, who became Stephen Uroš"s queen consort, and an unnamed son, who was killed at the Battle of Rusokastro in 1332.