A growing body of research has examined the relations of dispositions toward information and communication technology (ICT) to intercultural competence among university students. However, there is little research exploring the associations between ICT-related dispositions and intercultural competence among adolescent students. The mechanism of such relationships also remains unknown. Therefore, from a self-determination theory perspective, this study investigated the relationships of perceived autonomy, competence, and relatedness in ICT usage with global competence—intercultural knowledge, skills and attitudes—among 17,055 15-year-old students from Hong Kong, Macau and Taiwan in PISA 2018. Results of Multilevel Structural Equation Modelling (MSEM) analyses indicated that perceived autonomy in ICT use, perceived competence in ICT use and perceived relatedness in ICT use all positively affected intercultural knowledge, skills and attitudes. Further, the results of the study revealed that the use of social media was a partial mediator in the relationship between perceived autonomy/competence in ICT use and intercultural knowledge/skills; and between perceived relatedness/competence in ICT use and intercultural attitudes. Our findings emphasized the importance of satisfying students’ ICT-related needs and acknowledged the role of the use of social media in cultivating their global competence. Implications for teachers, schools and parents were discussed.