Low levels of agreement between adolescents and their parents or teachers on various cross-informant behavior rating scales have been reported in the literature. It is unclear whether one source of this inconsistency is adolescents’ tendency to underreport or overreport their behavioral problems relative to adult informants. The Child Behavior Checklist and its related forms were completed for a group of boys referred for school-based assessments due to academic and/or behavioral problems. Comparisons between the ratings of adolescents and their parents and teachers revealed little correspondence among informants, especially between adolescents and either their parents or teachers. Adolescents consistently under-reported behavioral problems relative to parents and teachers regardless of sub-sequent diagnosis (i.e., behavioral disorder, learning disability, or not diagnosed). Implications of this lack of agreement between adolescents’ self-reports and adult ratings in the school-based diagnosis of behavioral disorders are discussed.