Much of the research on regional lobbying in Brussels is based on single case studies, confined to particular policy areas and focused on the formal function and role these subnational authorities play in the European Union. This paper aims to offer a broader perspective and argues that a closer look to the presence of different organizational format in the representation of regional interests as well as the policy networks and coalition building between different regions may lead to a much more comprehensive and systematic perspective. Based on a new, comprehensive and novel dataset the paper demonstrates large differences among the territorial interest groups in terms of how they interact among themselves and key policymakers. Based on insights derived from transaction cost theory and exchange theory I will try to explain these differences by looking at the size of the region, the economic structure of the region as well as domestic institutional and political condition. In this way, the paper offers important insight on why territorial interest groups cooperate, on the bias in territorial interest representation and on their chances of influence in the Brussels scene.
