New academic self-concept instruments were used to measure self-concepts in 13 (Grades 5-6) or 16 (Grades 7-10) school subjects and to test the structure of academic self-concept posited in the Marsh/Shavelson model. First-order factor analyses identified the scales each instrument was designed to measure, demonstrating that academic self-concept is remarkably subject-specific. As posited, two higher order factors were sufficient to explain relations among core academic subjects, but additional higher order factors were needed to explain other school subjects (e.g., physical education, art, and music). The hierarchy, however, was weak, and much of the variance in specific subject self-concepts was unexplained by the higher order factors. Researchers interested in self-concepts in particular subjects are advised to use self-concept scales specific to those subject areas in addition, perhaps, to other measures of academic self-concept.