In a highly mobile and globalized educational market, Australian secondary schools attract increasing numbers of international students, the majority of whom are from China (Australian Education International, 2007). Most of these Chinese international students undertake two years of senior secondary education in this English medium context as a step towards entry to Australian tertiary institutions, but their increasing heterogeneity in terms of linguistic and academic ability is resulting in increasing frustrations for them and their subject teachers alike (Arkoudis & Love, 2004; Love & Arkoudis, 2006). This paper explores the language and learning needs of Chinese international students in one popular senior school subject, Specialist Mathematics, using student and teacher interviews focusing on a written examination. The interviews were examined through two theoretical lenses, that of Norton’s (2001) imagined communities and van Langenhove & Harre’s (1999) positioning theory, in order to explore how the imagined communities of the students and their teacher influence their investment in the teaching and learning context. The analysis highlights that the teacher and students’ actions and identities are influenced by their different imagined communities, which affect their motivation and investment in their current community of the Specialist Maths class.