Interest representation plays a systemic role in European Union (EU) policymaking and integration, recognized as such in the Treaty on European Union. Interest organizations supply technical and political information to the EU institutions, and EU institutions use interest organizations as agents of political communication. Interest organizations act as a proxy for an otherwise largely absent civil society, with a teeming population of groups advocating for every imaginable cause. Where groups are absent, so EU institutions have stimulated their formation. The result is a pluralist system of checks and balances, although the literature includes findings of “islands” resembling corporatist practice. EU institutions have designed a range of procedures in support of “an open and structured dialogue between the Commission and special interest groups,” now largely packaged as a “Better Regulation” program. Measures include funding for nongovernmental organizations (NGOs), consultation procedures accompanied by impact assessments, a Transparency Register to provide lobbying transparency, and measures for access to documents that enable civil society organizations to keep EU institutions accountable. A multilevel governance system further strengthens pluralist design, making it impossible for any one type of interest to routinely capture the diversity of EU decision-making. A key controversy in the literature is how to assess influence and whether lobbying success varies across interest group type. EU public policymaking is regulatory, making for competitive interest group politics, often between different branches of business whose interests are affected differently by regulatory proposals. There are striking findings from the literature, including that NGOs are more successful than business organizations in getting what they want from EU public policymaking, particularly where issues reach the status of high salience where they attract the attention of the European Parliament. A key innovation of the Lisbon Treaty involves a European Citizens’ Initiative, which takes dialogue between civil society and EU institutions outside the ecosystem inhabited by civil society organizations and EU institutions known as the “Brussels bubble” and into the member states.