From a comparative perspective, the principle of good faith occupies a unique position in Swiss constitutional law. Article 9 of the Swiss Constitution elevates this principle to the status of a fundamental right, granting individuals a legally enforceable claim to be treated in good faith by the organs of the state. Furthermore, good faith is enshrined as a constitutional law principle under Article 5(3) of the Constitution, thus becoming a central normative standard that permeates the entire legal system. Unlike the fundamental right in Article 9, which can be invoked against the state, the principle in Article 5(3) serves as a guiding norm that explicitly binds both state authorities and private persons. However, the Swiss Constitution does not contain a precise definition of good faith and its requirements. The concept is historically rooted in private law and has been dynamically developed by the Swiss Federal Supreme Court, which continues to refine its contours in constitutional law jurisprudence. In practice, good faith plays a crucial role in the application of the law. A prominent legal manifestation of good faith is an individual’s right to the protection of legitimate expectations, particularly when relying on incorrect advice or information provided by Swiss authorities.