Summary Mandatory sharing of individual-level data from clinical trials with the research community promises to accelerate medical research and improve public health. Clinical trial data sharing is fast becoming a gold standard for open science, and myriad research policies from funders, journals, and regulators now encourage or mandate sharing. Little attention, however, has been paid to the inherent trade-offs data sharing presents between openness and privacy. Even where an acceptable balance is struck, responsible data sharing will depend on explicit cooperation and trust across many stakeholders. Research Ethics Committees (RECs) play an important role in creating an environment that fosters such trust and cooperation. However, their role is circumscribed by the regulatory frameworks in which they operate and there are important differences between North America and Europe. International and national norms address data sharing to varying extents. Some enable data sharing by providing guidance on broad consent and appropriate privacy and security safeguards. There is less guidance on if and how RECs should review the effectiveness of access processes, or ensure researchers share data. Building on existing guidance, we explore how RECs could enable data sharing that benefits public health, while ensuring participant privacy and autonomous decision-making is protected. First, RECs could assess data sharing plans to ensure they adequately address privacy protection, provision of timely access, and oversight of research uses. Second, RECs could ensure consent forms provide for sufficiently broad access and reuse of data. As consent design drastically affects downstream conditions of data access and use, consent forms should adopt non-restrictive, standardized, and clear language. Consent processes should also inform participants of intended uses; safeguards; and limits to anonymity, confidentiality and withdrawal. RECs will have to consider in the context of a given trial whether data sharing should be mandatory to uphold scientific transparency, or whether participants could be able to opt-out or withdraw. Third, RECs will need to coordinate with access committees and other RECs to avoid gaps or duplication in data sharing oversight. Fourth, where participants have consented to data sharing, RECs could adopt a role – along with institutions, journals, and regulators – to hold researchers accountable for not sharing data. International efforts are currently underway to harmonize consent language, privacy protections, access processes, and research oversight across institutions and countries, in turn providing RECs more certainty, and fostering trust and cooperation across the data-sharing ecosystem.