The Self Description Questionnaire (SDQ) is a multidimensional instrument designed to measure seven facets of self-concept hypothesized in Shavelson's hierarchical model. The SDQ, along with measures of attributions and academic achievement, was administered to primary school students from two quite diverse populations. Separate factor analyses of responses from the two groups were quite similar and clearly demonstrated the seven factors that the SDQ is designed to measure. The small correlations among the different dimensions were similar for the two groups and consistent with the hierarchical structure in Shavelson's model. Consistent and predictable correlations were also observed between the different self-concept dimensions and: (1) attributions of responsibility for academic outcomes; (2) academic achievement; and (3) the sex of the student. Somewhat smaller sex differences were observed for students who attended single-sex classes suggesting that they might be using a different reference group in forming their self-concepts. Overall, these findings provide compelling support for Shavelson's model of self-concept and the construct validity of the SDQ. (Author)