Observing category exemplars in an interleaved manner is more beneficial for inductive learning than blocked (massed) presentation, a phenomenon termed the interleaving effect on inductive learning. However, people tend to erroneously believe that massed is more beneficial than interleaved learning, and learners prefer the former during self-regulated learning. We report four experiments designed to investigate whether explicit instructions, which include individual performance feedback and the interleaving effect results from previous research, can (1) correct metacognitive illusions regarding the interleaving effect, (2) promote self-employment of interleaving, and (3) facilitate category learning. In addition, the current study explored (4) whether the intervention effect is long-lasting and (5) transferable to learning of categories in other domains. Experiments 1–4 established the effectiveness of the instruction intervention to enhance metacognitive appreciation of the interleaving effect, to promote self-employment of interleaving, and to facilitate learning of new categories. The intervention effect was long-lasting (at least 24 h; Experiment 2), and transferable to learning of categories in different domains (Experiments 3 and 4). These findings support the practical use of the instruction intervention.