In the Iliad, Asteropaios (Greek: Ἀστεροπαῖος; Latin: Asteropaeus) was a leader of the Trojan-allied Paeonians along with fellow warrior Pyraechmes. Asteropaios was the son of Pelagon, who was the son of the river god Axios and the mortal woman Periboia, daughter of Akessamenos (Greek: Ἀκεσσάμενος). Asteropaios was a newcomer to the war at the start of the Iliad; he had only been in Troy for less than two weeks.

Asteropaios had the distinction in combat of being ambidextrous and would on occasion throw two spears at once. In Book XII of the Iliad as the Trojans attacked the Achaean wall, Asteropaios was a leader of the same division as the Lycian warriors Sarpedon and Glaucus, the division which pressed hard enough to allow Hector and his division to breach the wall.

In Book XXI, as Achilles is mercilessly slaughtering Trojan warriors alongside the river god Scamander and polluting the waters with dead bodies (including one of Priam's sons, Lycaon). With the river god pondering how he might stop Achilles, Achilles in turn attacks Asteropaios (himself the grandson of a river god) whom Scamander instills with courage to make a stand against Achilles.