Abstract. Although EU institutions and policies create additional opportunities for national interest groups to influence policy-making, not all domestic groups make use of the extended niche provided by the EU. Lagging Europeanization has often been explained by resource-based accounts, for instance the group's staff resources or financial strength determines the ability to Europeanize. This article explores an alternative explanation and analyzes the importance of ties that bind national interest groups to their constituencies, their critical resource dependencies and their immediate environment. Our main conclusion is that Europeanization is not just shaped by properties of the EU system, but also by the interest group's embeddedness in its immediate environment.Acknowledgements. This paper forms part of a larger project funded by the Fund for Scientific ResearchFlanders on the political strategies of interest groups that seek access to and influence over the EU's external trade policies with regard to the WTO (G