Melantheus (or Melanthius) was a goat-herd in the service of Odysseus at Ithaca. Disloyally, he sided with the suitors of Penelope against his master. His name, unexpectedly exotically, seems to mean 'black blossoms', from meias, 'black' and anthos, 'flower'.

The Greek word melanthos, however, also meant 'black-coloured' generally, so perhaps for Melantheus it simply indicates 'swarthy man'. This could be appropriate for a goat-herd leading a largely outdoor life. See also Melantho.