In the context of constitutional reform and renewal of the political system of Kazakhstan, scientific interest in historical forms of popular representation is growing. Kurultai, as a traditional institution of collegial decision-making among the Turkic and Mongolian peoples, represents a unique phenomenon combining the features of a deliberative assembly, a body for legitimizing power and a mechanism for achieving public consensus. The purpose of the study is a comprehensive theoretical and legal analysis of the genesis, content and evolution of the kurultai as an institution of popular representation, as well as an understanding of its modern interpretations in the context of the development of Kazakh statehood. The methodological basis of the research includes historical-legal, formal-legal and system-structural methods, which made it possible to trace the transformation of the kurultai institution from tribal assemblies to the modern model of popular representation. The study establishes that in the Kazakh Khanate the kurultai performed the functions of the supreme advisory body, participated in the legitimation of khan power, systematization of customary law and adoption of strategic decisions. Its key features are identified: representative character, collegiality, consensus-based decision-making and connection with customary law. It is concluded that the appeal to the institution of kurultai in modern Kazakhstan reflects the desire to harmonize borrowed models of representative power with national historical and cultural traditions.