Anselm is known for offering a distinctive definition of freedom of choice as “the ability of preserving uprightness of will for its own sake.” When we turn to Anselm’s account of the devil’s fall in De Casu Diaboli, however, this idiosyncratic understanding of freedom is not at the forefront. In that text, Anselm seemingly assumes a traditional understanding of free will defined in terms of alternative possibilities for the angels. These alternative possibilities must be present so the angels can engage in ‘self-determination.’ God, however, does not face alternative possibilities to achieve His self-determination. Anselm thus explicates his notion of free will in terms of three different concepts: his distinctive definition of free choice, self-determination, and the principle of alternative possibilities. Despite attempts (by both scholars and Anselm) to explain how these three concepts are related, I argue that their relationship is problematic. In particular, I argue that Anselm is guilty of conflating and equivocating with regard to these concepts. I further importantly claim that the conflation obscures the fact that his understanding of self-determination calls into question God’s excellence over that of the good angels.