Students are now living in a world that is both rapidly changing and complex. This study aims to examine the effects of school subjects and the classroom climate they create on 15-year-old students’ global competence. A multilevel analysis was conducted on a representative sample of 5,873 Hong Kong participants in PISA 2018. The results showed that student perception of a better classroom disciplinary climate contributes to their global competence directly (.07) and indirectly via their skills in mathematics (.03), science (.03), and reading (.07) at the student level, and indirectly via their skill in reading (.38) at the school level. In addition, about one-third (.32) of the variance of global competence was explained at the school level. These findings suggest that schools play an essential role in cultivating students’ global competence, via traditional learning in core subjects such as mathematics, science, and reading, and a good learning environment. Copyright © 2021 HKERA-APERA International Conference.