This article aims to expand both the analytical gaze of diplomacy studies and anthropological interests in the field of transnational think tanks, advocacy and policy advice. Drawing on ethnographic data from three such organisations, it investigates secrecy practices, focussing on how such practices amount to discreet diplomatic efforts. In a variety of ways, secrecy is utilised as a resource in foreign relations and diplomacy; it is a means to leverage status and influence. Although outwardly striving for transparency, think tanks use secrecy practices in their effort to establish themselves as actors of consequence in foreign relations and diplomatic circles. The practices of secrecy are part and parcel of the power games such organisations play, in which all participants learn and master what to discuss and what to keep silent about. These practices, however, pose a clear challenge to matters of accountability and transparency.