Shared between China and Kazakhstan, the basin of the Ili and Irtysh Rivers is of great importance to central Asia. China and Kazakhstan have developed relatively stable relationships in various fields, including through strategic economic, trade and defence partnerships. Nevertheless, with a high level of competition over water quantity, Kazakhstan has shown continuous concerns over the shared Ili and Irtysh river basins. The sharing of the Ili and the Irtysh Rivers has become a source of strain in foreign relations between the two countries. China’s diplomatic cooperation with Kazakhstan is complex. It has signed a water-sharing agreement with Kazakhstan, and the country has shown a commitment to cooperate in peacemaking activities, such as in flood control and drought relief. However, China’s diplomatic initiatives have not yet settled Kazakhstan’s disagreements. Such disagreements particularly relate to the division of water quantity, as water scarcity becomes an increasingly pressing domestic issue for both countries. It remains unclear how China can successfully tackle its water disagreements with Kazakhstan without having to make significant changes to its current water policies in Xinjiang.