AbstractWithin education, some teachers’ interpretation of professionalism emphasizes conformity to the perceived norms of collective associations. Unprofessional behaviour, often equated with ‘unethical’ behaviour, is seen by many to be that which threatens solidarity and loyalty to colleagues. Informal norms typified by casual collegial relations as well as more formal attachments to organized unions or teachers’ federations exert a significant influence on individuals’ behaviour within the group. Professional ethics, in this sense, become concerned primarily with how one relates to colleagues rather than how one fulfils moral responsibilities to students. Qualitative findings from interviews with elementary and secondary school teachers suggest that, as a result of an ethic of collegial loyalty, some teachers experience personal moral and ethical dilemmas that they find difficult to resolve. Some respondents acknowledged that this can enable serious situations to be ignored or ‘covered up’. This paper examines some of the tensions and dilemmas experienced by teachers and raises questions about the ethical adequacy of defining professionalism in terms of inter‐colleague behaviour.