Attachment theory proposes that experiences with the primary caregivers are an important basis for the development of close social relationships outside the parent-child relationship. This study examined the association between representations of attachment, as assessed with the Adult Attachment Interview (AAI), representations of friendship and peer relations, as assessed with an interview in a sample of 43 adolescents. Secure attachment representations were significantly related to interview-based assessments of close friendships, friendship concept, integration in a peer group, and emotion regulation within close friendships. Attachment experiences reported during the AAI, their integration, and their coherency were related to friendship quality and friendship concept. Results show the close associations between attachment representations and friendship relationships during adolescence. The associations between peer relations and attachment representations differed depending on whether an interview approach or a questionnaire approach was used.