This article presents the results of the impact study of the Nightingale Project, a social mentoring project, whose aim is to support the welcoming and social inclusion processes of adolescent students of foreign origin who recently arrived in Catalonia and who are currently enrolled in the country's schools. The more than one hundred mentoring pairs (mentor and mentee) that took part in the intervention project were administered a questionnaire (N=58). This same questionnaire was also given to a group of adolescents with the same profile but who did not participate in the project (N=128) and who were treated as a control group.After six months of intervention (which corresponds to the duration of the Nightingale Project), results show that students who participate in mentoring learn the language faster, create broader and more diverse networks of friends in school, develop higher educational aspirations and expectations, are better acquainted with the reception context (municipality they live in), and improve standards of self-confidence and self-esteem, among other characteristics. The research also demonstrates that mentoring aimed at adolescents, as is the case of the Nightingale Project, plays a key role in avoiding development of an oppositional identity and, conversely, helps facilitate a process of resilience in adolescents in the new context of reception.