This study examined the structure of adolescent self-concept (SC) structure for males and females by using three different measures of each SC facet in a covariance structure analysis of the data. Specifically, the purposes of the study were to: (1) test the hypothesis of the invariance of a multidimensional, hierarchical SC structure for males and females; (2) test the invariance of the discriminability of SC from academic grades for males and females; and (3) examine gender differences related to general SC, academic SC, English SC, mathematics SC, and grades in English and mathematics. The original sample consisted of 991 grade 11 and 12 students from two suburban high schools in Ottawa, Canada. Following deletion of missing data, the final sample size was 832 (412 males, 420 females). Different SC structures were found for males and females. The number and nature of the facets of SC were similar, but the hierarchical relations among the facets differed. Moreover, grades could be discriminated from their corresponding subject-specific SCs (i.e., subject-specific SC is not an alternate report of grades). Finally, girls obtained higher grades in English and mathematics than boys, but their mathematics SCs were significantly lower. (PN)