The issue of informant discrepancies about child and adolescent functioning is an important concern for clinicians, developmental psychologists, and others who must consider ways of handling discrepant reports of information, but reasons for discrepancies in reports have been poorly understood. Adolescent attachment and informant depressive symptoms were examined as 2 explanations for absolute and directional discrepancies about adolescent symptoms, relationships, and social behavior in a sample of 189 eleventh-grade students (mean age = 16.5 years). Adolescent attachment predicted absolute discrepancies, with greater attachment coherence associated with fewer discrepancies in reports of adolescent depressive symptoms, parent–adolescent conflict, and adolescent externalizing behavior. Parents’ but not adolescents’ depressive symptoms sometimes predicted absolute discrepancies. Mothers’ depressive symptoms and adolescent attachment predicted the direction of discrepancies for mother–peer reports only.