There is a wide and growing interest in promoting Research Data Management (RDM) and Research Data Sharing (RDS) from many stakeholders in the research enterprise. Funders are under pressure from activists, from government, and from the wider public agenda towards greater transparency and access to encourage, require, and deliver improved data practices from the researchers they fund.Funders are responding to this, and to their own interest in improved practice, by developing and implementing policies on RDM and RDS. In this review we examine the state of funder policies, the process of implementation and available guidance to identify the challenges and opportunities for funders in developing policy and delivering on the aspirations for improved community practice, greater transparency and engagement, and enhanced impact.The review is divided into three parts. The first two components are based on desk research: a survey of existing policy statements drawing in part on existing surveys and a brief review of available guidance on policy development for funders. The third part addresses the experience of policy implementation through interviews with funders, policy developers, and infrastructure providers. ‡ © Neylon C. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.In our review we identify, in common with other surveys, that RDM and RDS policies are increasingly common. The most developed are found amongst funders in the United States, United Kingdom, Australia, and European Union. However many other funders and nations have aspirational statements or are developing policy. There is a broad pattern of policy development moving from aspiration, to recommendations, to requirements, and finally reporting and auditing of data management practice.There are strong similarities across policies: a requirement for data management planning, often in grant submissions, expectations that data supporting published articles will be made available, and in many cases requirements for data archiving and availability over extended periods beyond grants. However there are also important differences in implementation.There is essentially no information available on the uptake and success of different policies in terms of compliance rates, or degrees of data availability. Many policies require a Data Management Plan as part of grant submission. This requirement can be enforced but there is disagreement on the value of this. One view is that requirements such as DMPs are the only way to force researchers to pay attention to these issues. The other is that such requirements lead to a culture of compliance in which the minimal effort is made and planning is seen as a "tick-box" exercise that has no further value. In this view requirements such as DMPs may actually be damaging the effort to effect culture change towards improved co...