The present study examined the dual mediating effects of self-efficacy and self-deception on the relationship between conscientiousness and learning over time. Data from 134 college students were used to investigate the relative impact of self-efficacy and self-deception. Consistent with the hypothesized model, conscientiousness was significantly and positively related to both early training self-efficacy and self-deception, and both self-efficacy and self-deception had significant effects on learning but in opposite directions. Furthermore, the relative impact of self-efficacy and self-deception on learning changed over time as expected. The negative effect of self-deception in early stages of training disappeared at later stages of training but the positive effects of self-efficacy remained. Support was not found for self-efficacy and self-deception as mediators of the conscientiousness-learning relationship.