This paper discusses how an ethical dimension can best be included within the policies, structures and services of the developing European Open Science Cloud (EOSC). Although the inclusion of ethical principles and policies are seen as of fundamental importance to the EOSC, it is difficult to anticipate all the ethical issues that may emerge as the scientific, technical, social and political landscape evolves. It is therefore seen as crucially important to have governance mechanisms in place that can ensure ethical issues are appropriately dealt with in the future, however and whenever they are presented, as well as identifying and proposing responses to current issues. An analysis of ethical issues relating to organisational conduct and policies, research conduct, research decision making, the use of data, especially sensitive personal data, and the interaction between science and society, serves to underline the complexity and diversity of potential issues.