In the genesis of China as a modern nation‑state, the relationship with the outside world played a fundamental role. The goal of this essay is to outline the fundamental factors that shaped the relationship between China and the League of Nations and between China and the Organization of the United Nations during and following the two world wars, offering an interpretative reading from the perspective of China’s transformation into a modern nation‑state. The choice to focus on these two international organisations is due to the fact that China’s bilateral relations with each specific country were very different, making generalisations quite difficult. Conversely, both the League and the United Nations can be considered as representing the world as a whole. As the two world wars were the most important international events in the first half of the twentieth century and prompted the establishment of the two most important, largest and most influential international organisations, China’s relations with the League of Nations and later with the United Nations during those periods represent an important case study for understanding the transformation of China’s international status and the world’s acceptance and recognition of China.