The original Egyptian version of Manetho's name is lost, but some speculate it means "Truth of Thoth", "Gift of Thoth", "Beloved of Thoth", "Beloved of Neith", or "Lover of Neith". Less accepted proposals are Myinyu-heter ("Horseherd" or "Groom") and Ma'ani-Djehuti ("I have seen Thoth").
In the Greek language, the earliest fragments (the inscription of uncertain date on the base of a marble bust from the temple of Serapis at Carthage and the Jewish historian Flavius Josephus of the 1st century AD) writes his name as Μανέθων Manethōn, so the Latinised rendering of his name here is given as Manetho (the same way that Platōn is rendered "Plato"). Other Greek renderings include Manethōs, Manethō, Manethos, Manēthōs, Manēthōn, and Manethōth. In Latin it is written as Manethon, Manethos, Manethonus, and Manetos.