The purpose of this article is to shed some light on the emerging, yet largely undefined, principle of openness in EU law. After addressing the semantic confusion existing between openness and transparency, it attempts – through a textual and systemic interpretation of their respective legal basis – to identify the normative content of the EU turn to openness. It then moves to explore the principle’s potential for attaining its declared Treaty-sanctioned objectives: promoting good governance and ensuring the participation of civil society in the democratic life of the Union. It illustrates that, although openness largely maintains an instrumental rationale – aimed at enhancing the quality of the regulatory outcome rather than at promoting a more inclusive process –, the institutional, substantive and societal landscapes surrounding its operation have changed in recent times. It demonstrates that these alterations may help to shift the understanding of openness in the EU away from a specific, unidirectional, bottom-up right of access to information to a much broader, proactive and top-down duty of the EU administration to genuinely open its vault of information to the public and create new avenues of participation for civil societies and other organised interests. The changing nature of the openness rights accompanied by the growing demand for more active participation inherent to our times is set to reinvigorate civic life and, more importantly, to ensure political legitimacy grounded in democratic values.