The chapter examines how the principle of good faith permeates the Convention for the Protection of Human Rights and Fundamental Freedoms. It departs from good faith as an instrument underlying international law. Using mainly doctrinal approach, it delves into reading of the Convention and the case law of the European Court of Human Rights. First, the chapter traces the good faith of States within substantive rights and freedoms in the Convention. Later, it looks at States’ procedural obligation to cooperate with the Court as a prerequisite for international adjudication. As a whole, the chapter proposes a systematics of and a reflection on understanding the principle of good faith in the Strasbourg system of fundamental rights protection.