What does it mean when a constitution characterises a state as a ‘social state’? This chapter examines the concept’s overall function. It describes the interventionist and welfare-oriented nature of states, which prevails worldwide today. It illustrates the emergence of the concept in intellectual history and shows how it is interpreted in jurisprudence and in the case law of constitutional courts, particularly in Germany, where the concept originated and became a model for other countries. Under the social state clause, the state is obliged to create society through legislation and establish interpersonal relations based on social justice. The interplay between the social state and social rights is also outlined. The social state clause establishes, guarantees and expands social rights to work, education, health, social security and social assistance. To this end, the state has created the appropriate institutions.