This article explores the strategies think tanks (TTs) from Brussels, London, Paris and Ljubljana use to exert influence on European Union (EU) policy-making. The paper argues that European TTs mobilise symbolic, political and network forms of capital built at the European level to enhance their legitimacy, credibility and visibility in the Brussels policy-making scene. The paper examines how TTs convert these forms of capital using the examples of the symbolic value of the 'TT' label, the role of expert providers, the strategic 'presence' in Brussels, and their membership in TT networks, and states the particular importance of symbolic and network capital in the EU policy context, which contribute to the legitimacy of the EU policy-making itself.