This article analyzes how Nordic trade unions cooperate with unions in Europe, and what actors and organizations they cooperate with to influence EU policies. We examine both similarities and differences between the Nordic countries and between unions in different sectors, and make some comparisons with unions in other European countries. As a background, we first present the Nordic model(s) of industrial relations, and some important national and sectoral differences. Thereafter follows an analysis based on a survey carried out in 2010-11. The results show strong similarities between the Nordic countries regarding transnational union cooperation and union action, but also that there is greater diversity between sectors than between countries. The internationally exposed manufacturing sector is the most engaged in transnational cooperation, followed by the construction industry. The more sheltered services sector has a somewhat lower degree of cooperation, and the professional/academic unions are the least engaged. This implies that, besides variation between countries, variation between sectors must be taken into account when analyzing the existence of a common Nordic approach to transnational cooperation.