Moral distress is a phenomenon that has been receiving increasing attention in nursing and other health care disciplines. Moral distress is a concept that entered the nursing literature – and subsequently the health care ethics lexicon – in 1984 as a result of the work done by American philosopher and bioethicist Andrew Jameton. Over the past decade, research into moral distress has extended beyond the profession of nursing as other health care disciplines have come to question the impact of moral (...) constraint on individual practitioners, professional practice, and patient outcomes. Along with increased interest in the phenomenon of moral distress have come increasing critiques – critiques that in their essence point to a serious lack of conceptual clarity in the definition, study, and application of the concept. Foundational to gaining conceptual clarity in moral distress in order to develop strategies to prevent and ameliorate the experience is a careful revisiting of the epistemological assumptions underpinning our knowledge and use of the concept of moral distress. It is our contention that the conceptual challenges reveal flaws in the original understanding of moral distress that are based on an epistemological stance that holds a linear conception of cause and effect coupled with a simplistic perspective of ‘constraint’ and ‘agency’. We need a more nuanced approach to our study of moral distress such that our ontological and epistemological stances help us to better appreciate the complexity of moral agents acting in organizational contexts. We believe that critical realism offers such a nuanced approach. (shrink)