This study examined proficiency levels and attitudes of main languages in use among ethnic minority students in Hong Kong. We surveyed 260 students from primary and secondary schools with English as the medium of instruction. They were multilingual speakers who were proficient in spoken English and Cantonese. Our results revealed asymmetric and correlated proficiency levels including in the students' native languages (L1s). Their multilingual proficiencies were also affected by factors such as age variables and associated with aspects of L1 attitudes. Our key finding corroborated previous research claims that mastery of multiple languages could allow ethnic minority students to construct a more powerful multilingual and multicultural identity.