The need for research to advance scientific understanding must be balanced with ensuring the rights and wellbeing of participants are safeguarded, with some research topics posing more ethical quandaries for researchers than others. Moral injury is one such topic. Exposure to potentially morally injurious experiences can lead to significant distress, including post-traumatic stress disorder (PTSD), depression, and selfinjury. In this article, we discuss how the rapid expansion of research in the field of moral injury could threaten the wellbeing, dignity and integrity of participants. We also examine key guidance for carrying out ethically responsible research with participants' rights to self-determination, confidentiality, non-maleficence and beneficence discussed in relation to the study of moral injury. We describe how investigations of moral injury are likely to pose several challenges for researchers including managing disclosures of potentially illegal acts, the risk of harm that repeated questioning about guilt and shame may pose to participant wellbeing in longitudinal studies, as well as the possible negative impact of exposure to vicarious trauma on researchers themselves. Finally, we offer several practical recommendations that researchers, research ethics committees and other regulatory bodies can take to protect participant rights, maximise the potential benefits of research outputs and ensure the field continues to expand in an ethically responsible way.