John Phrangopoulos or Frankopoulos (Greek: Ἰωάννης Φραγγόπουλος) was a Byzantine aristocrat and senior official in the Despotate of the Morea. Member of a noble family of Frankish origin, he was protostrator and katholikos mesazon (chief minister) under the Despot of the Morea Theodore II Palaiologos in 1428/9. In this capacity he surrendered the towns and fortresses of Messenia—Androusa, Kalamata, Pidima, , Nesin, Spitalin, Grembenin, Aetos, and —which he governed in the name of Theodore II, to George Sphrantzes as the representative of Theodore's brother, Constantine XI Palaiologos. In June 1443 he was witness, at Constantinople, of the exchange of appanages between Constantine and Theodore: Theodore took over Constantine's domain of Selymbria, while the latter became sole master of the