This paper presents a critical content analysis of the curriculum development process within the International Baccalaureate Primary Years Programme (IBPYP) using the Cultural-Historical Activity Theory (CHAT) framework. As a part of the globally recognised International Baccalaureate (IB) framework, the IBPYP has undergone significant growth. The study comprehensively examines eight key documents related to IBPYP curriculum development, with a focus on cultural components. It explores the program's historical evolution, educational philosophy, curriculum structure, and pedagogical approaches. Additionally, it analyses changes in cultural components. The research reveals that the transformation of the IBPYP from a theoretical framework to a practical curriculum signifies a strategic shift towards enhancing adaptability and relevance in diverse international contexts. The analysis identifies distinct phases in the IBPYP's document development: introductory, explanatory, and expectant. These phases reflect changes in curriculum content, terminology, and instructional strategies over time. This paper discusses the IBPYP's cultural components, evolution strategies, the transition from theory to practice, and challenges encountered. By shedding light on the IBPYP's development, it provides valuable insights for the future of international education. In summary, this research offers a deeper understanding of the IBPYP and its ongoing evolution, serving as a reference for shaping the direction of international education.