In Greek mythology, Atymnius (Ancient Greek: Ἀτύμνιος) may refer to:
Son of Zeus and Cassiopeia, a beautiful boy, who was beloved by Sarpedon. Others call him a son of Phoenix (mortal husband of Cassiopeia). He seems to have been worshipped at Gortyn in Crete together with Europa.
A Trojan warrior, son of Emathion and Pegasis. He was killed by king Odysseus.
A companion of Sarpedon, from Lycia. He was the son of Amisodarus (who had reared Chimera) and brother of Maris. Atymnius was killed by Antilochus, while Maris was slain by Thrasymedes.
Father of Mydon, charioteer of Pylaemenes.
