Melanthius (Ancient Greek: Μελάνθιος) was an ancient Greek painter of the 4th century BC. He belonged to the school of Sicyon, which was noted for fine drawing.

•  This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Melanthius". Encyclopædia Britannica. Vol. 18 (11th ed.). Cambridge University Press. p. 90.