In Greek mythology, Actis (Ἀκτίς) was one of the Heliadae, a son of Rhodos and Helios. Actis, along with his brothers, Triopas, Macar and Candalus, were jealous of a fifth brother, Tenages's, skill at science. They killed him and Actis escaped to Egypt. According to Diodorus Siculus, Actis built the city of Heliopolis in Egypt to honour his father Helios. It was from him that the Egyptians learned astrology.