The Student's Perception of Ability Scale (SPAS) was developed in response to a need for a reliable and valid instrument to measure academic, rather than general, self-concept in elementary school children. This scale was designed for use with children in Grades 3 to 6. Descriptive data on the SPAS were discussed in terms of its substantive, structural, and external validity. Normative data were given. More specifically, the scale was found to have six meaningful factors, good alpha and test-retest reliability, and strong discriminant and experimental validity. Validity data were presented which indicate that the SPAS clearly differentiates between children who have learning problems and those who do not, and that it correlates about .50 with school grades. The authors concluded that the SPAS measures a unique domain of academic self-concept and has good measurement characteristics. They also discussed possible practical and research implications for the scale. (Author/CTM)