The rapidly expanding and evolving landscape of data production and sharing is an opportunity for National Statistical Offices (NSOs) to exercise their expertise in the larger statistical as well as national data community. Indeed, because of this environment, NSOs must expand their role into data stewardship in order to fully carry out their mandate. As the transformation is multifaceted, there are different interpretations of how the NSO role can and should change, and what data stewardship means in this context. In this report, the United Nations Economic Commission of Europe (UNECE) Task Force (created by the Conference of European Statisticians in 2021) has examined the issue of data stewardship through the lens of NSOs. Data stewardship is viewed as operating in service of, rather than in control of the data ecosystem and reflects an overall paradigm shift or evolution of the framework that guides how NSOs operate, moving from the production of statistics to the provision of data and data-related services. The work of this Task Force has focused on defining and explaining the foundational concepts and frameworks relevant to data stewardship. More concrete guidance and recommendations could be developed at a later stage, as a follow-up to this report. The Task Force has considered further steps to support NSOs in implementing their stewardship role, which are summarised in Section 1.4 'Future work'. Ultimately, the report aims to serve as a guide to statistical offices regardless of data or structural maturity. It will help offices decide whether they should extend their role as government data stewards, as well as provide inspiration and ideas to those who are already performing this function. Public data holders will also gain a deeper understanding of the advantages and services provided by NSOs in the future data ecosystem.