Using data from interviews with Health Technology Assessment (HTA) professionals in Canada, this paper shows their views of the appropriate role of, and evidence required for, HTA are associated with values and norms. Recognizing HTA as a moral economy helps to explain when and why HTA professionals' views of what HTA should and can do are mutable, and may specifically help to explain why there is resistance among some HTA professionals to the inclusion of ethical issues and patients or the public in technology assessment. The moral economy framework furthermore sheds light on the nature of objectivity in contemporary HTA.