The medium of instruction (MOI) has been a bone of contention in Hong Kong, a former British colony, since its colonial days. Despite the Hong Kong government's effort to promote the "biliterate and trilingual" language policy, advocating Cantonese, English and Putonghua as the three official spoken languages and emphasizing the importance of literacy in both written Chinese and English, most tertiary institutions today still adopt English as the medium of instruction (EMI). However, with the expansion of tertiary education in the early 1990s and the decline in the general English language proficiency of university students, some university lecturers have found it difficult to teach in English as required. This raises the issue of the practicality of the indiscriminate adoption of the EMI policy at tertiary level, particularly at the self-financing tertiary institutions where students are generally known to have under-performed in the English subject. In order to understand whether or how the EMI policy is upheld in these institutions, focus group interviews were conducted with students from various programmes of five self-financing tertiary institutions in Hong Kong. The findings indicate these students' strong preference for English-medium instruction with the belief that it can improve their English proficiency, though their actual approaches to coping with the demand on their limited English and how they view and use the three languages in class deserve policy makers' serious consideration.