The present study explores the internationalisation of secondary schools. It focuses on the assessment of the intercultural competence (IC) of returnees who participated in an annual study-abroad programme offered by the Italian educational association Intercultura (a non-profit organisation). The precise aim of this research is to find possible assessment indicators of IC, specific to the context of student mobility in secondary schools. To reach this goal, a qualitative methodology was adopted; 21 semi-structured interviews were conducted with the returnees, their parents, friends, teachers and Intercultura volunteers. The findings suggest that the elements to be considered in assessing the IC of returnees should include, among others, curiosity towards people perceived as having different cultural backgrounds, interest in global issues, self-awareness, new understanding of home context, knowledge of host context, ability to make critical comparisons, adaptability and ethnorelative view.