In early adolescence, attachment security reflects not only the quality of ongoing relationships with parents, but also how adolescents process social relationships with "others"--that is, their "social value orientation"--with possible implications for adolescents' risk-taking. In this study, a sample of Italian early adolescents were administered self-report measures in order to examine the relationships (a) between early adolescents' perceived attachment security to mothers and fathers, social values (related to family and the socio-cultural context), and sensation seeking (as a temperamental predisposition to risk-taking), and (b) between these variables and adolescents' externalizing problem behaviour. Adolescents were more securely attached to the same-sexed parent. Further, attachment security with the opposite-sexed parent predicted more conservative social value orientations, and lower levels of problem behaviour. In contrast, sensation seeking predicted self-enhancement and openness-to-change values to a greater extent, and, in girls, lower levels of attachment security to mothers and fathers.