Students' agency in decision-making processes has aroused the interest of scholars in the field. However, little attention has been paid to how students themselves critically reflect on their roles when interacting in intercultural school environments. This study uses qualitative data from secondary school students in Greece to describe the ways in which they critically challenge structural and institutional inequalities and move away from practices akin to functional interculturalism. Our findings offer new evidence suggesting that the more mature students' intercultural thinking is, the more intercultural responsibility they develop. However, as they become more interculturally responsible, they commence informal leadership roles that make them demand a world free from injustices while focusing on how to combat them.