This is a novel investigation of whether, and how, a single close supportive friendship may facilitate psychological resilience in socio-economically vulnerable British adolescents. A total of 409 adolescents (160 boys, 245 girls, four unknown), aged between 11 and 19 years, completed self-report measures of close friendship quality, psychological resilience, social support, and other resources. Findings revealed a significant positive association between perceived friendship quality and resilience. This relationship was facilitated through inter-related mechanisms of developing a constructive coping style (comprised of support-seeking and active coping), effort, a supportive friendship network, and reduced disengaged and externalising coping. While protective processes were encouragingly significantly present across genders, boys were more vulnerable to the deleterious effects of disengaged and externalizing coping than girls. We suggest that individual close friendships are an important potential protective mechanism accessible to most adolescents. We discuss implications of the resulting Adolescent Friendship and Resilience Model for resilience theories and integration into practice.