This study examines the interplay among language proficiency, use and attitudes of Shenzhen-Hong Kong cross-border students (CBS), a unique group of Hong Kong students who reside in Shenzhen and attend school in Hong Kong. A questionnaire survey of over 500 CBS reveals that Putonghua is their dominant language, followed by Cantonese, while their hometown dialect and English play peripheral roles. CBS show strong preferences for Putonghua, both instrumentally and integratively. Statistical analyses indicate significant correlations between CBS’ proficiency in the four languages and their attitudes towards them. The study identifies pairwise associations among CBS’ use of Cantonese at school, their proficiency in the language, and their attitudes towards it, forming a reinforcing cycle. However, no such patterns were found for Putonghua or English. The study concludes that improving CBS’ Cantonese proficiency and emotional connection to the language is essential for their integration into Hong Kong society, addressing identity challenges, and fostering a cohesive sense of belonging. Copyright © 2024 Informa UK Limited, trading as Taylor & Francis Group.