This article reports on a qualitative study that examined the identity construction experiences of six international English-language teaching assistants (IELTAs) in a large English medium of instruction university in Hong Kong. The study explored the contribution of the IELTAs to the internationalization goals of the university using a framework of teacher identity construction. The study illustrates that the IELTAs faced significant challenges in constructing their identities as teachers, and that identity conflicts that arose with students at the host university could threaten the IELTAs' contributions to the internationalization goals of the university. The article draws upon aspects of critical discourse analysis to explore the reactions of the IELTAs to these conflicts and reveals how, through the exercise of agency and the emergence of an evolving community of practice, the IELTAs constructed their preferred teacher identities. Implications for the design of IELTA programs in analogous educational settings and future research are also considered. (Contains 1 table.)