Despite widely reported 'Mainland-Hong Kong conflicts', recent years have witnessed progressive growth of Mainland Chinese students in Hong Kong universities. This study aims to explore the role of Willingness to Communicate (WTC) in the cross-cultural adaptation of such a group of sojourning students. Structural equation modelling showed that the competence in L2 communication played a significant role in L2 WTC, which had an influential effect on academic adaptation, which was itself identified as a mediator between psychological adaptation and socio-cultural adaptation. Implications for curriculum design and instructional practice on international students are discussed.