The term 'altruism' is often used without definition, leading to contradictions in what we expect from medical students. In this reflection paper, we critique the concept of 'altruism' from the perspective of moral philosophy and social psychology and challenge its unquestioned usage within the medical education literature, especially that emerging from the USA. We will argue that 'altruism' is a social construction with a particular history, stemming from Kantian philosophy and perpetuated within newer disciplines such as social psychology. As it currently stands, 'altruism' seems to mean utter self-sacrifice--a position contradictory to recent recommendations by regulatory bodies in the UK, which suggest that graduates should look after the 'self' and achieve a work-life balance. In this article, we argue that it is undesirable to have 'altruism' as a learning outcome for medical students and we also argue that 'altruism' is not an observable behavior that can be measured. Instead, we suggest that medical educators should employ a more balanced term, borrowed from the social psychology literature i.e. pro-social behavior. We argue that whilst 'pro-social behavior' focuses on actions that benefit others, it does not do so at the expense of the self. In addition, it focuses on students' observable behaviors rather than their inner motivations, so is measurable. We conclude our article by discussing the formation of physicians based upon a virtue ethics, where society and the profession are in dialogue about the telos of medicine and its virtues, and where the character of the young physician is formed within the crucible of that dialogue. Thus, central to this pro-social behavior is the concept of phronesis or prudence, including the balancing of self-interest such as self-care, and the interests of the other.