Contrary to general belief, ethical progress as a means to attain the divine and thereby achieve salvation occupies a central place in the Nag Hammadi writings. Plato's conception of the homoiosis theo or "likeness to god" fits very well this dynamic view of man, since it optimistically claims the possibility of human development and progress. Plato's dialogues are far from offering a univocal exposition of how this progress was fulfilled, but later Platonists show a rather systematizing tendency. The present paper provides an overview of the homoiosis theo in the Platonic dialogues and evaluates its appropriation by both Middle Platonism and the world of Gnosis. It also offers an exposition and analysis of those Nag Hammadi writings that may allow a proper understanding of the meaning and goal of the homoiosis theo in this collection of texts. Contrary to general belief, ethical progress as a means to attain the divine and thereby achieve salvation occupies a central place in the Nag Hammadi writings. Plato's conception of the homoiosis theo or "likeness to god" fits very well this dynamic view of man, since it optimistically claims the possibility of human development and progress. Plato's dialogues are far from offering a univocal exposition of how this progress was fulfilled, but later Platonists show a rather systematizing tendency. The present paper provides an overview of the homoiosis theo in the Platonic dialogues and evaluates its appropriation by both Middle Platonism and the world of Gnosis. It also offers an exposition and analysis of those Nag Hammadi writings that may allow a proper understanding of the meaning and goal of the homoiosis theo in this collection of texts.