Debates surrounding national and international identity are becoming increasingly prevalent with the rise of nationalist and populist rhetoric in the public sphere. International schools, which are growing in number, serve as valuable sites for conducting research on national and international identity as they can be viewed as a representation of the increasing diversification of many schools around the world. The aim of the study described in this article is to determine how the national and international identities of young people are influenced by being educated in this context. The conceptual frame of the study brings together a variety of concepts related to identity, categorised under national identity, transnational identity and cosmopolitan identity. In addition, the concept of 'third space' is drawn upon to reflect on the individualised process of negotiating identity. The study, undertaken with two international schools in Belgium and Serbia, found that attending an international school influenced students in a variety of ways, with some students strengthening their sense of international identity and others their national affiliation. It also emerged that the curricula and culture of these two schools promoted a hierarchy of identities, with the highest value awarded to Anglo-Western identities.