AIM: Extrahepatic biliary atresia is a rare disorder. This creates challenges in the quality and quantity of research conducted. This issue is exacerbated by the potential heterogeneity in the reported outcomes in research examining the management of biliary atresia. A core outcome set is required to standardise reporting on the management of biliary atresia in research, facilitate systematic reviews that include outcomes of greatest importance to patients and clinicians, and to evaluate the quality of the existing evidence base on the management of biliary atresia. METHODS: A list of all potential outcomes will be developed through a systematic review of the literature. This list will be refined through a three-stage Delphi approach, involving key stakeholders in the management of biliary atresia. This will include patients and their parents, clinicians, nurses and allied health professionals. In this way, outcomes will be prioritised into a set of consensus core outcomes. CONCLUSION: The development of a core outcome set in biliary atresia management is needed to guide future research and assist in evaluating the quality of existing research. ETHICS AND DISSEMINATION: Ethical approval has been granted by the Children's Health Queensland Hospital and Health Service Human Research Ethics Committee (HREC), Ref: HREC/20/QCHQ/62448. Results of the study will be published in an open access format.