Comprehending interest group politics is central to studying the European Union's (EU) policy shaping and decision-making, in education as in other policy areas. Yet the contribution of non-governmental organisations (NGOs) to EU policy shaping and decision-making in European education has been overlooked. Drawing on organisational studies, this article presents the results of an embedded case study of two Brussels-based NGOs, one representing a sectorial interest and the other a broader interest in education. The author examines their organisational features, funding sources, relations to EU institutions and the advocacy tools they use to strengthen civil society's voice at the European level. She argues that these NGOs act as agents in a double-loop transmission rather than simple transmission belts as depicted in the literature. She draws attention to their increased dependency on EU funds and constant need for alliances and coalition building as two aspects which may limit their freedom or increase internal competition in the future. Determining whether this reflects a more general trend in the advocacy work of Brussels-based NGOs will require expanding attention to other NGOs active in education and across sectors.