Two studies are reported presenting the development of the Adolescent Friendship Attachment Scale (AFAS), a 30 item self-report measure of adolescent close friendship conceptualized as an attachment relationship. Study One reports the results of exploratory and confirmatory factor analyses with a sample of 490 adolescents aged 13 to 19 years. A second-order factor model was supported with a single friendship attachment factor underlying three first order factors (Secure, Anxious/Ambivalent, Avoidant) similar to those reported in the broader attachment literature. The AFAS subscales were found to be appropriately reliable and demonstrated appropriate convergent and discriminant validity when compared to measures of attachment styles (the Relationship Questionnaire) and parental and peer group attachment (the Inventory of Parent and Peer Attachment). Study Two reports a successful replication of the factor structure with an independent sample of 787 adolescents. Further research evaluating the predictive utility of the AFAS is recommended.