Around the world, 4.3 million students are engaged in international education each year. However, there is a paucity in theory and empirical research on teachers' professionalism in international education. This paper aims to fill out this gap and contribute to our understanding of teachers' changing roles and identity due to the impact of internationalisation and the growth of international students. Drawing on positioning theory as a conceptual framework to understand teachers' roles and identity, this paper shows the emergence of teacher sub-identities as a reciprocal intercultural learner and an adaptive agent. It argues that these sub-identities are central to teachers' development of cosmopolitan qualities in the contemporary context of international education.