Simple SummaryConcepts typically used for human research ethics are beginning to be applied to animals in research. This paper focuses on the concept of participant dissent, and examines the options researchers can pursue and the consequences of these options, if researchers take the dissent of research animals seriously.AbstractIncreasingly, ethical concepts ordinarily reserved for the human research setting have been applied to nonhuman animals in research. This comes at the same time as concerns mount over challenges in translating the results of biomedical research with animals to human clinical benefit. This paper argues that applying the concept of dissent derived from research with humans to the context of animals can help to address a number of these translational issues, thereby providing an epistemological reason to take animal dissent seriously. This epistemological rationale can be added to the practical and ethical reasons for attending to animal dissent. Having made a case for recognizing the dissent of animals in biomedical research, the consequences that follow from this for the conduct of research are discussed. If animal researchers attend to dissent, then it seems that there are three types of strategy available: to override dissent, to train animals in such a way as to circumvent potential dissent, or to alter how research is conducted in order to be responsive to dissent. Only this last option has the potential to address all the types of reasons that motivate us to take dissent seriously; however, this would involve a significant reshaping of the practice of animal research.