This paper examines practitioners' experiences of global citizenship education (GCE) in an international baccalaureate (IB) international school and argues that the school's enactment of GCE constitutes an allosyncratic response. The author defines allosyncracy as the uniqueness of behaviour and temperament demonstrated by groups and individuals in relation to others of difference. Thinking with Jürgen Habermas and Elliot Eisner, the author elaborates allosyncracy and argues that the delineating and expressive properties of the concept form a useful thread for GCE advancement. This research will be of interest to those seeking to develop modes of global engagement, including global citizenship, cosmopolitan education, and international-mindedness.