Abstract By selecting the cases of the 2005 UNESCO Convention on the Protection and Promotion of the Diversity of Cultural Expressions and the agreement of cultural protocols in trade agreements between the European Union and third countries, this article explains why and how the third sector should be considered in analyses of regulatory co-operation at the international level. The article investigates key triggers of regulatory competition and how non-governmental organizations and broader coalitions of third-sector actors played a key role in fostering co-operation.