Academic effort is a key construct in research on motivational variables such as interest and in research on conscientiousness, one of the Big Five domains of human personality. Surprisingly, the two lines of research have rarely been brought together. In this chapter, we describe the differences and similarities in the theoretical foundation of the two constructs and review research on their predictive power for academic effort. We then introduce the Conscientiousness x Interest Compensation (CONIC) model which postulates that conscientiousness and interest (partly) compensate for each other in predicting academic effort. Subsequently, we present empirical evidence for the model. In the final section of the chapter, we formulate some next steps in a research program on conscientiousness and interest.