ABSTRACT With the expansion of transnational language learning and teaching, chances have increased for language teachers to work in crosscultural teaching contexts and regulate their emotions in the face of crosscultural emotional challenges. This study investigated the emotion regulation strategies employed by language teachers in crosscultural teaching contexts. Through a qualitative multi-case study with six Chinese as a second language (CSL) teachers in China, data collected from semi-structured interviews, class observations, and teacher reflective journals revealed seven emotion regulation strategies of three categories: restraining and pretending of surface acting; reframing, reconcentrating, and repositioning of deep acting; releasing and relieving of genuine expressing. These three categories reflected language teachers’ three experiences to cultural differences: deliberate minimisation, reflective acceptance, and communicative adaptation. The identified emotion regulation strategies also revealed two paradoxes existing in teacher-student interactions in crosscultural language teaching, which can be summarised as the Chinese idiom ‘round outside and square inside’. The study also proposed practical implications for language teachers’ emotion regulation and offered suggestions for institutions concerning teacher emotion in crosscultural teaching contexts.