Conscientiousness and interest are well-known predictors of academic effort and achievement. As hypothesized by the Conscientiousness × Interest Compensation (CONIC) model, conscientiousness and interest can (partly) compensate for each other, leading to (comparatively) high effort if either conscientiousness or interest is high. The present research (a) provides a test of this prediction across four school subjects, (b) examines whether the compensatory interaction can also be found when academic achievement is the outcome instead of academic effort, and (c) probes for the compensatory interaction when interest is replaced by utility value as a predictor variable. A total of 830 students in Grades 5 to 12 participated in this study. We assessed their conscientiousness and measured task value beliefs, academic effort, and achievement in 4 school subjects (German, English, mathematics, and biology). The predictions of the CONIC model were supported in all 4 subjects. In addition, we found compensatory interactions between conscientiousness and interest in predicting both academic effort and achievement. Furthermore, we observed similar compensatory interactions between conscientiousness and utility value. In sum, the results suggest a broader applicability of the CONIC model than originally proposed.