For the butterfly genus, see Iolaus (butterfly).

In Greek mythology, Iolaus ( Iólaos) was a Theban divine hero, son of Iphicles and Automedusa. He was famed for being Heracles's nephew and for helping with some of his Labors, and also for being one of the Argonauts. Through his daughter Leipephilene, he was considered to have fathered the mythic and historic line of the kings of Corinth, ending with Telestes.