Drawing on 171 in-depth interviews with physicists at universities in the United States and the UK, this study examines the narratives of 48 physicists to explain the concept of ethical ambiguity: the border where legitimate and illegitimate conduct is blurred. Researchers generally assume that scientists agree on what constitutes both egregious and more routine forms of misconduct in science. The results of this study show that scientists perceive many scenarios as ethically gray, rather than black and white. Three orientations to (...) ethical ambiguity are considered—altruism, inconsequential outcomes, and preserving the status quo—that allow possibly questionable behavior to persist unchallenged. Each discursive strategy is rationalized as promoting the collective interest of science rather than addressing what is ethically correct or incorrect. The results of this study suggest that ethics training in science should focus not only on fabrication, falsification, and plagiarism and more routine forms of misconduct, but also on strategies for resolving ethically ambiguous scenarios where appropriate action may not be clear. (shrink)