Why does Odysseus kill the suitors?

Odysseus kills the suitors in The Odyssey because they have violated his household, threatened his family, and broken the sacred customs of hospitality and marriage.

For years, the suitors have lived in Odysseus’s palace, feasting on his wealth while pressuring Penelope to marry one of them. Their behavior is an attack on Odysseus’s authority as king, Penelope’s loyalty as wife, and Telemachus’s place as son and heir. Telemachus names their crime early when he warns them, “You should be ashamed yourselves, mortified in the face of neighbors living round about! Fear the gods' wrath—before they wheel in outrage and make these crimes recoil on your heads.” Their offense is social, religious, and political at once.

The suitors also progress from greed to direct violence. They plot to murder Telemachus on his way home, and Antinous even proposes killing him secretly in Ithaca. When Odysseus returns disguised as a beggar, several suitors abuse him, revealing how little they respect strangers, beggars, or Zeus’s laws of hospitality. Antinous throws a stool at him, Eurymachus throws another, and Ctesippus flings a hoof. Odysseus endures this cruelty because he is waiting for the right moment to punish them.

Once Odysseus strings the bow and reveals himself, the suitors try to blame Antinous and offer repayment, but Odysseus refuses. Their crimes cannot be fixed by money because they have dishonored his wife, son, home, and kingship. He declares, “No fear of the gods who rule the skies up there, no fear that men's revenge might arrive someday—now all your necks are in the noose—your doom is sealed!” With Athena’s help, he and Telemachus kill them.

The slaughter is brutal, but within the poem’s moral world it is presented as vengeance and justice. The suitors’ greed, arrogance, and violence turn Odysseus’s homecoming into a test of whether order can be restored after years of dishonor.