The concept of the constituent power emerged in the revolutions of the 17th and 18th centuries. Classical theories have implied a strong link between the constituent power and a single organ of the state in which the powers of sovereignty were concentrated. This chapter argues that learning from the lessons of post-revolutionary constitution-making by internal and external actors can greatly help in solving the problem of imperfect procedural justice. It then considers the legitimate role of domestic and international actors in the non-revolutionary constitution-making. The chapter concludes that prior to the adoption of a constitution, international advisory and monitoring bodies as deliberative institutions legitimately take part in the national constitution-making procedure. After the adoption of a constitution, international courts as decision-makers may legitimately review the process of national constitution-making and constitutional norms on the basis of universal human rights and constitutional standards.