The Self Description Questionnaire (SDQ) is a multidimensional instrument designed to measure seven facets of self-concept hypothesized in Shavelson's hierarchical model. Fifth and sixth grade students completed the SDQ and several other instruments. Factor analysis of their responses clearly demonstrated the seven factors that the SDQ was designed to measure. Teachers were also asked to evaluate each student's self-concept along the same seven dimensions, and a multitrait-multimethod analysis offered support for both the convergent and divergent validity of the self-concept dimensions. Not only was there substantial student-teacher agreement on the seven dimensions, but agreement on any one dimension was relatively independent of agreement on other dimensions. The pattern of small correlations among the student self-concept dimensions was generally consistent with those observed for the teacher ratings and those predicted by the hierarchical model upon which the instrument was based. Student and teacher ratings of students' self-concept both showed similar and predictable correlations with attributions for academic achievement, sex of student and reading achievement, thus offering further support for the construct validity of the SDQ. (Author)