The Portuguese legal order foresees a broad duty to disclose instrumental and non-instrumental administrative information, i.e. both information related to ongoing administrative procedures and information that should be made available to all citizens. After a short investigation to determine the underlying constitutional values of (the right to) administrative transparency, this article scrutinizes the regime of access to administrative information in Portugal. Apart from its objective and personal scopes, determining its bearers and its addressees, this paper focuses on both the administrative procedure, on the one hand, and administrative and judicial guarantees, on the other.