Inefficient study skills increase the probability that study work is perceived as difficult and aversive, with procrastination as a likely result. As a remedy, more effective study skills and habits may be encouraged. However, research indicates that good study skills and habits may not by themselves be sufficient to remedy problems, as this relationship may be mediated by efficacy beliefs related to academic functioning. We investigated this hypothesis across three student samples (total N = 752). As predicted, structural equation modeling (SEM) indicated that study self-efficacy mediated the study habits--procrastination relation. The mediation effects were medium to large. We conclude that training of, and advice on, study skills and habits should be accompanied by measures that build study self-efficacy.