Manthos or Matthaios Papagiannis (Greek: Μάνθος or Ματθαίος Παπαγιάννης, ? – died between 1580 and 1596) was a Greek noble and revolutionary. He was involved in various plots to overthrow Ottoman rule in the northern regions of Epirus. For many years, Papagiannis attempted to convince various rulers of Western Europe to lend him military support for an uprising against the Ottoman Empire.