In this thesis I develop a virtue-theoretic conception of critical thinking. I argue that many conceptions of critical thinking have conflated “critical thinking” with “good thinking”. In contrast to other intellectual pursuits, I identify critical thinking as its own activity which aims at the achievement and maintenance of intellectual autonomy. I identify the constitutive virtues of critical thinking as conscientiousness, self-awareness, and prudent wariness. I argue that virtues require internal success, and intellectual autonomy is the achievement of the external success of the critical thinking virtues. It is a mistake to consider other virtues or character traits involving moral or cooperative behaviour as constitutive of critical thinking, though these may be ancillary virtues and useful to foster alongside the virtues of critical thinking. The conception I offer in this thesis suggests a solution to concerns regarding transfer of learning and offers a pedagogically-clear way of framing a critical thinking curriculum.