Between 2014 and 2018, more than 70,000 unaccompanied and separated children (UASC) arrived in Italy by sea, 90 per cent of whom were between 15 and 17 years old. The significant presence of UASCs in the country, and the growing number of UASCs who have turned 18 (about 60,000 in the last five years), have highlighted the need to understand the factors that affect the transition to adult life of UASCs in Italy, facilitating or hindering it, both individually and structurally. The research – commissioned by UNICEF, the United Nations High Commissioner for Refugees and International Organization for Migration – was carried out by ISMU Foundation in collaboration with Roma Tre University and University of Catania. The research has highlighted, first of all, the artificiality of a distinction between “children” and “adults” (UASCs who turned 18) that does not take due account of the transitional process of becoming adults, the sociocultural and gender differences that affect this process and the vulnerabilities to which this category of migrants, refugees and asylum seekers are exposed to. The analysis also shows a prevalent incidence of contextual, subjective and relational variables relating to the personal resources, agency and resilience of boys and girls, as well as the networks of formal and informal relations activated upon arrival.