Five personality scales, developed without regard to theory, were administered to 96 high school students. The correlations of these scales with four standard measures of academic achievement were compared with personality-achievement correlations from previous studies that used personality scales derived theoretically. These latter correlations were no larger, a result interpreted to mean that personality-achievement correlations are not enhanced by the use of theoretically derived personality scales. This interpretation is discussed in terms of previous hypotheses and Type I errors. Consideration is given to the five personality scales and to their relations with achievement. In particular, adaptiveness is related to reading achievement. About 25% of achievement variance is accounted for by personality, and about 50% by personality plus IQ. (Author/HH)