Theodore Paleologus (; – 21 January 1636) was a 16th and 17th-century Italian nobleman, soldier and assassin. According to the genealogy presented on Theodore's tombstone, he was a direct male-line descendant of the Palaiologos dynasty, which had ruled the Byzantine Empire from 1259 to its fall in 1453. Though most of the figures in the genealogy can be verified to have been real historical figures, the veracity of his imperial descent is uncertain.