This paper explores the quality and usefulness of ethical guidance for humanitarian aid workers and their agencies. We focus specifically on public health emergencies, such as COVID-19. The authors undertook a literature review and gathered empirical data through semi-structured focus group discussions amongst front-line workers from health clinics in Cox's Bazar, Bangladesh and in the Abyei Special Administrative Area, South Sudan. The purpose of the project was to identify how front-line workers respond to ethical challenges, including any informal or local decision-making processes, support networks, or habits of response.The research findings highlighted a dissonance between ethical guidance and the experiences of front-line humanitarian health workers. They suggest the possibility: (1) that few problems confronting front-line workers are conceived, described, or resolved as ethical problems; and (2) of significant dissonance between available, allegedly practically oriented guidance (often produced by academics in North America and Europe), and the immediate issues confronting front-line workers. The literature review and focus group data suggest a real possibility that there is, at best, a significant epistemic gulf between those who produce ethical guidelines and those engaged in real-time problem solving at the point of contact with people. At worst they suggest a form of epistemic control-an imposition of cognitive shapes that shoehorn the round peg of theoretical preoccupations and the disciplinary boundaries of western academies into the square hole of front-line humanitarian practice.