In Greek mythology, Dymas is the name attributed to at least four individuals.
The first Dymas was a Phrygian king and father of Hecuba (also called Hecabe), wife to King Priam of Troy. King Dymas is also said by Homer to have had a son named Asius, who fought (and died) during the Trojan War - not to be confused with his namesake, Asius son of Hyrtacus, who also fought (and died) before Troy. The scholiasts credit Dymas with another son, named Otreus, who fought the Amazons a generation before the Trojan War. The father of Phrygian Dymas is given as one Eioneus, son of Proteus, by some ancient mythographers (scholiasts on Euripides). Dymas's wife is given as Eunoë, a daughter of the river god Sangarius. In fact, Dymas and his Phrygian subjects are closely connected to the River Sangarius, which empties into the Black Sea. The etymology of the name Dymas is obscure, although it is probably non-Hellenic. Any resemblance to the name Midas, another mythical king of Phrygia, may be entirely coincidental.
The second Dymas was perhaps the same as the first. According to Quintus Smyrnaeus this Dymas was the father of Meges, a Trojan whose sons fought at Troy.
The third Dymas was a Dorian and the ancestor of the Dymanes. His father, Aegimius, adopted Heracles' son, Hyllas. Dymas and his brother, Pamphylus, submitted to Hyllas.