The notion of divine infinity is important in Gregory of Nyssa's theology; it is even argued by Ekkehard Mühlenberg that Gregory was the first to ascribe infinity to God. In this article key texts on divine infinity in Gregory, taken from Contra Eunomiun, De Vita Moysis, and In Canticum Canticorum, are discussed. It appears that Mühlenberg's interpretation has to be nuanced. Furthermore, dealing with divine infinity Gregory was able to link his thought with that of Philo of Alexandria. In the second part of this article, we discuss the question of God's infinity in Philo. Henri Guyot defends the thesis that Philo was the first to put forward the notion of divine infinity. Although Guyot's thesis can be criticised—Philo never calls God infinite—there are starting-points for this view in Philo.