This chapter analyses the role of the German Federal Constitutional Court’s case law regarding the national and international realm. In the first section, it examines the procedural requirements and the Court’s role within the legal system and deals with the erga omnes effect of its decisions. The second section discusses the Court’s citation practice with regard to its own precedents and its so-called standard-setting technique. In the third section, the importance of references to decisions of other national courts is analysed, taking into account the highest courts as well as the constitutional courts of the Länder. This allows us to draw conclusions about the overall interrelations of different courts within the German legal system. Subsequently, the fourth section approaches the question of how the Federal Constitutional Court deals with the case law of international courts. Given its integration into the network of European constitutional courts, the particularly important relationships with the European Court of Justice and the European Court of Human Rights will be examined more closely. Lastly, the reception of foreign court decisions in the Federal Constitutional Court’s case law will be studied against the backdrop of the discussion on judicial comparative legal reasoning.