 The notion of medieval practical reason can be investigated in two ways: 1) in light of the distinction between practical and theoretical sciences in the writings of the medieval university masters in the thirteenth and fourteenth centuries; 2) in comparison to the modern understanding of practical reason as described by Immanuel Kant. The first method allows for a strict adherence to the texts themselves, wherein the concept of ‘ratio practica’ is strictly limited to a type of philosophical reasoning. The second approach permits a deeper philosophical consideration of the parallels between the medieval understanding of the nature of moral goodness and the modern view of the will as practical reason. Both approaches are helpful in gaining a fuller understanding of the meaning of practical reason in the Middle Ages.