This paper views the enhancement of students' self-concepts as a high priority for school psychologists. It focuses on the theory, research and implications for practice regarding academic self-concept. Four models of the structure of self-concept and their resulting implications for practice are reviewed: (1) nomothetic; (2) taxonomic; (3) compensatory; and (4) hierarchical. Marsh's (1987) Big-Fish-Little-Pond effect on academic self-concept is discussed, with implications for the possible impact on academic self-concept of placement into remedial or accelerated programs, movement between varying types of school systems, or the possibility that parents who place their children into highly competitive educational programs may actually achieve exactly the reverse of their intended goals. The document concludes with a brief overview of recent research on academic self-concept underway at the University of Maryland, stressing the implications for practice resulting therefrom. (Author/NB)