Secrecy and informality rather than transparency traditionally reign trade negotiations at the bilateral, regional, and multilateral levels. Yet, transparency ranks among the most basic desiderata in the grammar of global governance and has been regarded as positively related to legitimacy. In the EU’s case, transparent trade diplomacy is quintessential for constitutional—but also for broader political—reasons. First, even if trade matters fall within the EU’s exclusive competence, the EU executive is bound by the Treaty on the Functioning of the European Union (TFEU) to inform the European Parliament, the EU co-legislator, in regular intervals. Second, transparency at an early stage is important to address public reluctance, suspicion, or even opposition regarding a particular trade deal. This chapter chronicles the quest for and turning moments relating to transparency during the EU trade negotiations with Canada (CETA); the US (TTIP), and various WTO members on services (TiSA).