Background: Embedding the concept of "international mindedness" in teaching across a range of subject matter is seen as increasingly important in today's education. Understanding the situated challenges that teachers may encounter in doing this is critical to the development of effective professional development in different socio-cultural and instructional contexts. Purpose: This study examined the enactment of international mindedness in International Baccalaureate diploma programmes (IBDP) in the Hong Kong context, focusing on the subject of Chinese language teaching. Sample: Nine experienced Chinese language teachers in IBDP programmes from six International Baccalaureate schools participated in the study. The schools were selected on the basis that they had some variety in student demographic profiles and organisational structures and had been offering the IBDP programmes for several years. Participant teachers either had several years of teaching IBDP Chinese or were holding leadership roles in the Chinese department and were very familiar with IBDP Chinese teaching. Design and methods: Individual, semi-structured interviews of approximately an hour's duration were conducted with participant teachers. A thematic analysis technique was used to analyse the interview data both deductively and inductively. Findings: Analysis revealed a set of internal and external challenges that were described as arising from the characteristics of the individual teachers, the curriculum and the teaching contexts. Challenges internal to the teachers included their educational experience, pedagogical beliefs and interpretations of the concept of international mindedness in teaching. External challenges included the characteristics of the IBDP curriculum, the subject matter and schools' and parents' expectations concerning international mindedness. Teachers and schools were found to utilise various strategies in order to enhance the perceived compatibility and relevancy of international mindedness in the curriculum. Strategies included balancing educational approaches and curriculum demands, enhancing communication with the school community around international mindedness, and providing school-based on-site training and monitoring. Conclusions: The study highlighted the need to take a localised approach which focuses on supporting schools and teachers to identify different models and pedagogies that are appropriate for their particular teaching contexts.