Second language (L2) teaching and learning is mediated by imagined community involving positioning learners themselves or being positioned by others in possible worlds. This research explores how Chinese language subject teachers in Hong Kong imagine the possible memberships of the communities in which South Asian learners will participate, and how the imagination makes a difference to their pedagogies and classroom practice. Through classroom observations and interviews with 14 secondary school teachers, research findings illustrate that the teachers treat South Asian learners as legitimate ethnic minorities in Hong Kong, while labeling them as illegitimate Chinese language users and second-class citizens in the host society. This imagination, while reflecting the subordinate position South Asians occupy, has an impact upon the teachers' pedagogies and classroom practice, which are oriented to the instruction of basic language knowledge, albeit being sensible of South Asian culture and customs. The research results suggest that imagining L2 learners as multilingual individuals and legitimate L2 users is a necessary condition to break the structural constraints on L2 acquisition.