The study of interest representation is well established in the context of the European Union 1 (EU). For more than five decades, scholars have debated the role played by interest groups (particularly business interests) in comparison to other policy actors in the ‘bottom-up' process of European integration. Recently, scholarship about the EU as a political system has shifted to focus on the ‘top-down' impact of the EU on national and sub-national actors, a process referred to as Europeanization. This article addresses lacunae in that literature and brings fresh evidence to light by exploring the EU effect on UK and French business interest representation. Drawing on a combination of political and management studies concepts and tools, this article compares and contrasts UK and French firms located in two industrial sectors directly affected by the EU's single market programme, namely the telecommunications and energy sectors. The research, an extensive qualitative study based on more than 50 elite semi-structured interviews, elicits the firms' and other actors' perceptions, understandings and impressions of each other and the political processes at work. Some important similarities and differences between the UK and French firms emerge from the data. Most significantly, some narrowing in the dissimilarities is apparent, which may, in part, be attributed to the process of Europeanization itself.