Emotion in medical education rests between the idealised and the invisible, sitting uneasily at the intersection between objective fact and subjective values. Examining the different ways in which emotion is theorised within medical education is important for a number of reasons. Most significant is the possibility that ideas about emotion can inform a broader understanding of issues related to competency and professionalism. The current paper provides an overview of three prevailing discourses of emotion in medical education and the ways in which they activate particular professional expectations about emotion in practice. A Foucauldian critical discourse analysis of the medical education literature was carried out. Keywords, phrases and metaphors related to emotion were examined for their effects in shaping medical socialisation processes. Despite the increasing recognition over the last two decades of emotion as 'socially constructed', the view of emotion as individualised is deeply embedded in our language and conceptual frameworks. The discourses that inform our emotion talk and practice as teachers and health care professionals are important to consider for the effects they have on competence and professional identity, as well as on practitioner and patient well-being. Expanded knowledge of how emotion is 'put to work' within medical education can make visible the invisible and unexamined emotion schemas that serve to reproduce problematic professional behaviours. For this discussion, three main discourses of emotion will be identified: a physiological discourse in which emotion is described as located inside the individual as bodily states which are universally experienced; emotion as a form of competence related to skills and abilities, and a socio-cultural discourse which calls on conceptions from the humanities and social sciences and directs our attention to emotion's function in social exchanges and its role as a social, political and cultural mediator. © Blackwell Publishing Ltd 2013.