Transparency is essential to ensure the credibility and legitimacy of international trade and investment negotiations. Besides its external dimension (the access of the general public to information), in the European context there is also an internal dimension to the concept – referring to the exchange of information between different European institutions. Pursuant to the Treaty on the Functioning of the European Union, the European Parliament has the right to be regularly informed by the European Commission during the negotiation of any trade agreement. The exercise of this right is, however, constrained by the existence of rules concerning the creation and management of official secrets. These rules may obscure the Parliament’s understanding of relevant issues, thus limiting its ability to exercise democratic control. While the promotion of a high degree of transparency helps to strengthen democratic scrutiny, accountability and legitimacy of the European trade policy; it is also necessary to safeguard confidential or sensitive information and ensure productive, orderly negotiations, so as not to jeopardise the interests of the Union. This article argues that the regulatory framework currently in place strikes a proper balance between these diverging interests and enables the European Parliament to effectively perform its oversight powers.