Background: Recent government initiatives in Hong Kong have focused on raising the participation of students from South Asian backgrounds in mainstream schools, to encourage their further integration into Hong Kong's educational system and society. These students' learning in mainstream schools takes place within the context of the central curriculum and, thus, students face the challenge of learning Chinese as an additional language. Mainstream schools sometimes provide additional support, including the provision of bilingual teaching assistants to address the specific needs of the students from South Asian backgrounds. Purpose: This exploratory study aims to investigate the roles of bilingual teaching assistants in Hong Kong. Method: Interviews were held with two bilingual teaching assistants from the South Asian community in Hong Kong who were working in a mainstream secondary school. Teachers from the school were also interviewed. Open-ended interview questions focused on perceptions of the roles and responsibilities of bilingual teaching assistants in Chinese-language-medium classes. The data were analysed to identify any emergent patterns and themes. Findings: The research findings indicate that the bilingual teaching assistants from the South Asian community not only took on the role of helping the learners from South Asian backgrounds in Chinese language acquisition, but also acted as cultural mediators between mainstream school culture and the culture of the South Asian community in Hong Kong. Conclusions: This small-scale exploratory research study suggests the importance of the role of bilingual teaching assistants in promoting equal access to quality education for ethnic minorities in Hong Kong.