We explore how the growth mindset relates to intercultural and global citizenship competencies in three Southeast Asian countries (Indonesia, Philippines, Thailand). Using data from the global competencies self-report survey and cognitive assessment of PISA 2018, we hypothesized that intercultural attitudes (i.e., openness, respect, global mindedness) will be positively associated with cognitive global competence, and that growth mindset will amplify this positive association, consistent with research on the benefits of possessing a growth mindset. Separate hierarchical multiple regression analyses for each country indicated partial but substantial support for the hypotheses. In all countries, growth mindset boosted the relationship between global mindedness and global competence; growth mindset also enhanced the relationship between respect and global competence, except in Indonesia. Growth mindset did not enhance the positive association between openness and global competence. The results provide additional support for the benefits of growth mindset in a learning domain that has previously not been extensively studied; specifically, in strengthening the links between intercultural attitudes and global competency, but not for the more surface attitude (openness). The results indicate how the psychological mechanisms associated with growth mindset could create pathways to strengthening global citizenship competencies.