Ioane Petritsi (XII century Georgian Neoplatonic philosopher) habitually translates the terms of Neoplatonic metaphysics into language fitting the Christian spiritual universe. With this respect it is quite interesting how does he deal with the Neoplatonic notion of light and enlightenment. What is the status and function of light in his philosophy? This question relates both to the ontological and epistemological functions: on the one hand light is effusion from the sole source – the One – its intensity and power diminishing with every successive stage of reality; on the other hand, light is the cognitive and revertive principle, accounting for a lower term’s understanding and return to its source. Moreover, light is a certain divine presence in human soul, through which the latter is able to behold spiritual realities. Now, is this light immanent to human, as belonging to his very essence, or a presence of transcendent Logos in him, which is also called “Light”? I shall discuss possibility of Petritsi’s dependence on not only Neoplatonic sources, but also Eastern patristic sources, most significantly Gregory of Nazianzus and Pseudo-Dionysius the Areopagite.