A number of characters have the name Melanippus in Greek mythology.
One of the better known ones was the son of Astacus, who participated in the war described in the myth Seven Against Thebes. In the story, the twin brothers Eteocles and Polynices clashed against each other, trying to win over the throne of Thebes. Melanippus, being on the side of Eteocles, defended the gate called Proitid against the hero Tydeus, whom he successfully killed along with Mecisteus. He was killed by Amphiaraus, Capaneus, or Tydeus just before he died.
Another Melanippus was a citizen of Patrae, who fell in love with Comaetho. However, the parents of both lovers had a rivalry between them and forbade the two of them to see each other. Melanippus and Comaetho secretly met in the temple of the goddess Artemis and slept together. Artemis, enraged by their behaviour, put a curse in the region, bringing plague and famine. The oracle of Delphi instructed the citizens of Patrae that the two lovers had to be sacrificed and that the most good looking man and woman would be sacrificed every year, until a new god or goddess appeared in the city. So it happened, until the god Dionysus was introduced to Patrae shortly after the fall of Troy.