Moral courage is characterized as a bystander intervention against the norm violations of a perpetrator despite the potential for negative consequences for oneself. We tested a comprehensive set of potential personality determinants of moral courage derived from a model of helping. In Study 1, we used a vignette to assess the self-reported willingness to intervene against a theft. In Study 2, the theft was put into effect, and behavioral reactions were observed. The results of Study 1 showed that moral disengagement, self-efficacy, and social anxiety, which are traits that are known to predict helping, were also related to moral courage intentions. Differently, in Study 2, real moral courage was predicted only by beneficiary sensitivity, a disposition that captures perceptual readiness and affective reactivity to perceived injustice. Our results provide insights into the processes involved in moral courage in a realistic situation and stress the importance of behavioral observations.