Matthew Asen Kantakouzenos or Cantacuzenus (Greek: Ματθαῖος Ἀσάνης Καντακουζηνός, Matthaios Asanēs Kantakouzēnos, c. 1325 – June 1383)[1] was Byzantine Emperor from 1353 to 1357 and later Despot of the Morea from 1380 to 1381.

With five thousand Turks, Matthew tried to re-establish his former appanage along the Serbian-Byzantine border by attacking this region, but failed to take Serres.

He was soon defeated in battle in late 1356 or early 1357 by a Serb army under Vojvoda Vojihna, who was the holder of Drama (a major fortress in the vicinity).

After imprisoning Matthew first on Tenedos, then on Lesbos under the watchful eye of Francesco I Gattilusio, John forced him to renounce the imperial title.

After his brother's death in 1380, Matthew Asanes Kantakouzenos governed the Morea until the appointment of the new governor Theodore I Palaiologos, in 1381, and his arrival in 1382.