(Ἄγριος), a son of Porthaon and Euryte, and brother of Oeneus, king of Calydon in Aetolia, Alcathous, Melas, Leucopeus, and Sterope. He was father of six sons, of whom Thersites was one. These sons of Agrius deprived Oeneus of his kingdom, and gave it to their father; but all of them, with the exception of Thersites, were slain by Diomedes, the grandson of Oeneus. (Apollod. 1.7.10, 8.5, &c.) Apollodorus places these events before the expedition of the Greeks against Troy, while Hyginus (Fab, 175, comp. 242 and Antonin. Lib. 37) states, that Diomedes, when he heard, after the fall of Troy, of the misfortune of his grandfather Oeneus, hastened back and expelled Agrius, who then put an end to his own life; according to others, Agrius and his sons were slain by Diomedes. (Comp. Paus. 2.25.2; Ov. Ep. 9.153.)

There are some other mythical personages of the name of Agrius, concerning whom nothing of interest is known. (Hesiod. Theog. 1013, &c.; Apollod. 1.6.2, 2.5.4.)