Modelli di relazioni con i coetanei e adattamento psicosociale in adolescenza: una ricerca cross-nazionale e longitudinale - The study is aimed at constructing a typology of patterns of peer relationships in Italy and the Netherlands and at investigating the longitudinal relationships with beliefs and expectations about relationships and school, psychological discomfort and antisocial and risky behaviour. 439 adolescents of both gender, aged from 15 to 20 years participated at the study. We described four patterns of 158 peer relationships: Isolated (dimension of network, time spent with friends and support perceived by friends were all low), Deep (only perceived support was high; more frequent among girls in both countries), Superficial (only quantitative aspects were high; more frequent among boys), Integrated (both quantitative and qualitative aspects). We found both stability (higher among Superficial and Integrated) and change (higher among Isolated and Deep). The Isolated showed the lowest beliefs and expectations and involvement in risk behaviours, the Deep and the Superficial showed intermediate levels of both beliefs and risk behaviour, and the Integrated showed the highest levels. We also found a great similarity in the links among relational models, beliefs, psychological discomfort and risk behavior in Italian and Dutch adolescents. However, when adopting the same relational model, the Italians perceived higher sense of alienation and depressive feelings and were more involved in lying and disobedience than the Dutch.