One of the most dangerous forms of wrongdoing in healthcare occurs when harm no longer appears as wrongdoing at all. The failures at Mid Staffordshire National Health Service Foundation (NHS) Trust illustrate this phenomenon: substandard practices became so embedded in routine clinical life that they ceased to be recognised as ethically problematic. Drawing on Diane Vaughan’s concept of the normalisation of deviance, this article examines how repeated departures from established standards, once tolerated and legitimised by organisational processes, can erode the conditions that ordinarily underpin individual responsibility. It argues that intention-based accounts of culpability are inadequate where practitioners no longer perceive their conduct as a significant breach of norms. Building on accounts of culpable ignorance and affected ignorance, the article argues that responsibility for wrongdoing in healthcare must be understood as both graded and distributed across individuals and institutions. Responsibility varies according to differences in role, authority, awareness and practical capacity, while institutions bear responsibility where they tolerate or cultivate conditions in which moral attention is diminished and unsafe practice becomes normalised. The article concludes that a defensible account of responsibility in healthcare must extend beyond isolated intentional acts to include the organisational conditions that shape what agents are able to recognise, question and resist.