School-based counselling is an effective intervention for psychological distress in adolescents, but little is known about the processes leading to a therapeutic change in a Chinese sociocultural context. Twenty-five Chinese senior secondary school students and eight school counsellors in Hong Kong were interviewed, and the data were analysed thematically within a critical realist paradigm. Three change processes were developed: new ways of thinking, developing better relationships and experiencing positive emotions. The study's findings were broadly consistent with previous research into school-based counselling in Western contexts but not consistent with previous studies carried out with adult Chinese clients. Counselling in schools has the potential to deliver significant benefits to adolescents in Hong Kong.