Acusilaus (Greek Άκουσίλαος) was an ancient Greek historian and mythographer. All his works are lost, and are known only from references by later writers.
According to the Suda, he was an Argive from Kerkis, near Aulis, in Boeotia, and wrote genealogies based on bronze tablets which his father, Kabas, had dug up near his home. Josephus tells us he lived shortly before the Greco-Persian wars of the early 5th century BC, and his genealogies sometimes differed with those given by Hellanicus and Hesiod. According to Plato, he said that Earth and Love were the first gods born of Chaos. Clement of Alexandria and Julius Africanus tell us that he considered that Phoroneus, who ruled the Argives until the year of the first Olympiad (776 BC), was the first man on earth. We know from pseudo-Apollodorus that he made reference to the myth of Artemis and Actaeon. Clement says that although some number him among the seven wise men, he plagiarised his works from those of Hesiod. Tatian dismisses him as a writer of myths.
- Suda, Alpha, 942
- Josephus, Against Apion 1.13
- Josephus, Against Apion 1.15
- Plato, Symposium 178b
- Julius Africanus, Fragments of the Chronology 13.3
- Clement of Alexandria, Stromata 1.21
- Pseudo-Apollodorus, Library 3:4.4 (2nd century AD)
- Clement of Alexandria, Stromata 1.14
- Clement of Alexandria, Stromata 2.2
- Tatian, Address to the Greeks 24