Why do some interest groups express more policy preferences than others during open consultations organized by the European Commission? This article examines this question by testing an explanatory framework that emphasizes the inter‐organizational context in which lobbying takes place and interest groups' resource endowment. The empirical analysis focuses on environmental policy‐making. The findings show that interest groups' preference articulation behaviour is largely influenced by the number of inter‐organizational linkages they have with other stakeholders. Resource endowment matters in that resource‐rich interest organizations are found to be less likely to articulate their preferences via open consultations. Interest groups' organizational form is also a relevant predictor of the likelihood they articulate preferences: in consultations, European federations voice more preferences than national or individual organizations.