In Greek mythology, Mimas was one of the Gigantes who waged war upon the Olympians. As one of the Gigantes, he was born when the blood of Uranus fell upon Gaea. According to Apollodorus, Mimas was defeated by Hephaestus with "missiles of red-hot metal". However, in Ion by Eurpides, Mimas is defeated by Zeus with a thunderbolt and, in Gigantomachia by Claudian, he is defeated by Ares.
After his defeat, Mimas was buried under Prochyte, an island off the coast of Naples.
A giant named Mimon is depicted on a frieze of the Siphnian Treasury at Delphi. This is likely the same as Mimas.