In Greek mythology, Lynceus /ˈlɪnˌsuːs/ or /ˈlɪnsˌjuːs/ (Ancient Greek: Λυγκεύς) was a king of Argos, succeeding Danaus.
Lynceus was named as a descendant of Belus through his father Aegyptus, who was the twin brother of Danaus. Danaus had fifty daughters, the Danaides, while Aegyptus had fifty sons including Lynceus, whose name means "lynx-eyed" (from Latin).
Aegyptus commanded that his sons marry the Danaides and Danaus fled to Argos, ruled by King Pelasgus with his daughters. When Aegyptus and his sons arrived to take the Danaides, Danaus gave them to spare the Argives the pain of a battle. However, he instructed his daughters to kill their husbands on their wedding night. Forty-nine followed through, but one, Hypermnestra refused because her husband, Lynceus, honored her wish to remain a virgin. Danaus was angry with his disobedient daughter and threw her to the Argive courts. Aphrodite intervened and saved her. Lynceus later killed Danaus as revenge for the death of his brothers. Lynceus and Hypermnestra then began a dynasty of Argive kings (the Danaid Dynasty) beginning with Abas. In some versions of the legend, the Danaides, minus Hypermnestra (or sometimes alternately Amymone) were punished in Tartarus by being forced to carry water through a jug with holes, or a sieve, so the water always leaked out.