We distinguish between social and liberal collective skill formation systems and demonstrate that the German VET system is a social system with a strong (parity) role for trade unions in its governance. In contrast, unions play a considerably weaker role in the more liberal Swiss system, which privileges employers’ interests. We show that the different position of unions in VET systems has the expected consequences on a range of indicators. We further examine why unions are less important in Switzerland and show how, after the First World War, differences in the institutional environment and power resources of the union movements set Germany and Switzerland on different paths, which are still visible today.