The intention of this paper is to provide an overview of the ethical aspects of social market economy, with particular attention to the role of the legal system. The author demonstrates that a legal system has an auxiliary role to the system of values at the core of social market economy. Besides, it promotes the practical realisation of the values inherent in the idea. Liberty, justice and equality are the three pillars of social market economy. Only under these conditions can business entities participate in market competition on the basis of equal opportunities. The paper breaks new ground by pinpointing the interdependence between the practical implementation of value systems in the market economy and the supporting role of the legal system, as well as by identifying the common roots of social market economy and the modern legal system of Germany, which dates back to the Weimar Republic, when law concepts based on neo-Kantism were developed and when the fundamentals of the ordoliberal theory were laid down (the Freiburg School).