The development of a modified semantic differential measure of school-related attitudes of grades 3-6 children is described and its validation involving 99 children is reported. Each of the four scales of this measure, Attitude Toward-School, -Language Arts, -Teachers, and -Arithmetic, was found to be unidimensional. Internal consistency estimates were in the range .89 to .97 for the two administrations. Canonical correlations of the pre- and post-attitude measures with respect to the June, 1980 and June, 1981 Canadian Tests of Basic Skills (CTBS) Vocabulary, Reading, Language Arts, Mathematics Concepts, and Mathematics Problem-Solving scores were .42 and .41. Redundancy analysis indicated that only small amounts of redundant variances were accounted for in the pre- and post-data sets. Results are discussed from measurement and instructional perspectives. (Author)