In Greek mythology, Eurypylus (Ancient Greek: Εὐρύπυλος, "Broadgate") was the son of Telephus, king of Mysia. A great warrior, he led a Mysian contingent that fought alongside the Trojans against the Greeks in the Trojan War, and was killed by Achilles' son Neoptolemus.

Eurypylus' father was Telephus, who was the son of Heracles, and was the king of Mysia in Asia Minor. Telephus' mother was Auge, the daughter of Aleus, the king of Tegea, a city in Arcadia, in the Peloponnese of mainland Greece. Auge ended up at the court of the Mysian king Teuthras, as his wife, and Telephus became Teuthras' adopted son and succeeded Teuthras as king. According to one account, Telephus' wife was Laodice, the daughter of Priam, king of nearby Troy, while according to another, Telephus married Agriope a daughter of Teuthras. However, accounts that mention Eurypylus' mother, say that she was Astyoche, who was (usually) Priam's sister.

In a prelude to the Trojan War, the Greeks attacked Mysia, mistaking it for Troy. Eurypylus' father Telephus was wounded by Achilles and later, when his wound continued to fester, was also healed by Achilles. Because of this (according to some accounts), Telephus promised that neither he nor his family would aid the Trojans in the coming war. Nevertheless, during the final stages of the war, between the death of Achilles, and the ruse of the Trojan Horse, Eurypylus led a large Mysian force to fight on the side of Troy. Eurypylus was a great warrior, and killed many opponents, including Machaon, Nireus, and Peneleus. But Neoptolemus finally killed Eurypylus, using the same spear that his father Achilles had used to both wound and heal Eurypylus' father Telephus.

Homer has Odysseus say that Eurypylus was, next to Memnon, the most beautiful (κάλλιστον) man he had ever seen. By some accounts Priam obtained Eurypylus' aid in the war by giving his mother Astyoche a golden vine, or by promising Eurypylus one of his daughters as wife. According to Servius, Eurypylus had a son, Grynus, who became king in Mysia and was known as the eponym of Gryneion and the founder of Pergamon.

The earliest mention of Eurypylus occurs in Homer's Odyssey. In the underworld, Odysseus meets Achilles' ghost who asks Odysseus to tell him about his son Neoptolemus. Odysseus tells how, during the fighting at Troy, Achilles' son killed a great warrior, the magnificent and beautiful Eurypylus, son of Telephus. And that Eurypylus, and many others with him, had died because of "womanly gifts".

Homer says nothing more about these "gifts". But, if Telephus's promise not to aid the Trojans was a tradition known to Homer, then Eurypylus' appearance at Troy might have required some explanation, to which the "gifts" might refer. Later commentators on Homer offered two explanations of these "gifts". A scholion to this Odyssey passage says that, according to the 6th century BC mythographer Acusilaus, Eurypylus' mother was Astyoche, and that Priam, the king of Troy, asked Eurypylus, who had inherited his father Telephus' kingdom of Mysia, for aid in Troy's war with the Greeks. But Eurypylus refused Priam's request because of his mother. So Priam gave Astyoche a golden vine, and she sent her son to Troy. From other scholia on the same Odyssey passage, and a scholiast on Euripides, we learn that Astyoche was Priam's sister, and that the golden vine was a family heirloom, made by Hephaestus, and given by Zeus to an earlier king of Troy (either Tros or Laomedon) in compensation for Zeus' abduction of his son Ganymede. These other Odyssey scholia also give an alternate explanation of Homer's "gifts", saying that Priam had offered to give Eurypylus one of his daughters to be his wife.

Eurypylus's exploits at Troy apparently formed part of the Little Iliad (c. 7th century BC?), one of the poems of the Epic Cycle. According to the 2nd century AD geographer Pausanias, the Little Iliad told of Eurypylus killing Machaon. Proculus, in his summary of the Little Iliad, says that Eurypylus came to the aid of the Trojans and was slain by Neoptolemus. Eurypylus's confrontation with Neoptolemus was likely one of the poem's set-piece battles.

According to Plutarch, the duel between Eurypylus and Neoptolemus also featured in some work of Sophocles, and the play Eurypylus mentioned by Aristotle, was probably that work. The Sophoclean play had a messenger, reporting on Eurypylus's death to his mother Astyoche, tell of Priam lying upon Eurypylus's mangled corpse saying "Ah, my son, I betrayed you, though I had in you the last and greatest hope of salvation for the Phrygians. Though you were not our guest for long, you will leave the memory of many sorrows... neither Memnon nor Sarpedon caused so many sorrows, though they were foremost among spearmen." The play also had Astyoche reproach herself and Priam, saying: "the lord of Ida, my brother Priam, who in all foolishness persuaded me, wretch, to do an accursed act." The irony of Achilles' son, killing Telephus' son, using the same spear that Achilles had used to heal Telephus, apparently also figured in the tragedy.

Dictys Cretensis, in his 4th century AD retelling of the Trojan War, adds several details to Eurypylus' story. Priam, in addition to giving Eurypylus a golden staff, and many other beautiful gifts, finally won Eurypylus' support, by offering him his daughter Cassandra in marriage. In the decisive battle Eurypylus was the leader of the combined Mysian and Trojan forces, and when he was finally killed by Neoptolemus, the Trojans, having placed all their hopes on Eurypylus, fled the battle and were routed. Neoptolemus ordered Eurypylus's body removed from the battle and carried to the ships, and after the battle the Greeks "cremated Eurypylus and sent his bones, in an urn, back to his father, for we remembered his father's kindness and friendship".

The most detailed account of Eurypylus' role in the Trojan War is given in Quintus Smyrnaeus's 4th century AD epic poem the Posthomerica, which told the story of the final stages of the War. The poem covered the events between Hector's funeral, and the fall of Troy. Eurypylus appears as a principal character, in books six through eight of the poem. In book nine, Eurypylus is buried, by the Trojans, at Troy, in front of the Dardanian Gate.

Book six of the poem, describes Eurypylus coming to Troy, his first night there, and his victorious first day of battle. Eurypylus "the seed of mighty Hercules" arrives in Troy with a "great host", while:

As Eurypylus arms himself, nearly one hundred lines of the poem are devoted to a detailed description of Eurypylus' shield, adorned with a depiction of the twelve labors of Hercules. Dressed for battle, Eurypylus "seemed the War-god", and seeing him Paris addressed him, saying: