This study examined attachment, coherence, and self-disclosure as predictors of intimacy in adolescent friendships as well as the extent to which coherence and disclosure mediate the relationship between attachment and intimacy. Gender and grade-level effects on intimacy development were also examined for one hundred ninety-six seventh, eighth and ninth grade students (116 boys and 80 girls). Attachment, coherence, and disclosure strongly predicted intimacy. Self-disclosure and coherence also interacted to influence intimacy where a tendency toward self-disclosure contributes to intimacy to a greater extent at low (when compared to high) levels of coherence. Structural Equation Modeling indicated that only coherence and self-disclosure had a direct effect on intimacy. Avoidant and anxious attachment had an indirect affect on intimacy, and were mediated by coherence and disclosure. Clinical implications of the results are discussed.