This article applies sociological neo-institutionalism to help understand transnational trade union wage policy. We review existing approaches to the role of trade unions as organizational actors in wage bargaining coordination and contrast these with the concepts of organizational fields and institutional work. Besides structural and associational power, transnational institutions are also able to increase the ability and willingness of unions to act transnationally. We draw empirical evidences from existing studies on European wage bargaining coordination in metalworking.