Theophilos Palaiologos (; died 1453) was the cousin of emperor Constantine XI Palaiologos, or was at the very least of the Palaiologos family. Theophilos commanded Hellenic troops during the Fall of Constantinople. Known as a grammarist, humanist, and mathematician, Leonard of Chios says of him that Theophilus was 'of noble linage and deep scholarship'. The Greek historian and near contemporary of the fall of Constantinople Laonikos Chalkokondyles describes in book eight of his "Histories" Theophilos 'fighting in a manly way to the end', choosing to die rather than see his country and family in captivity.