--- - |2 Abstract The present research meta‐analytically examined the effects of preparing‐to‐teach and subsequent teaching (relative to mere studying without teaching expectancy) on the acquisition of domain knowledge. The synthesis of 28 studies indicated that the estimated effect sizes (Hedges' gs) were 0.35 for preparing‐to‐teach and 0.56 for teaching with preparing‐to‐teach. Both preparing‐to‐teach and teaching with preparing‐to‐teach were effective in promoting deep learning (as well as surface learning) and even after a delay. The learning benefits of teaching with preparing‐to‐teach were larger when students expected and engaged in an interactive teaching activity than when they expected and engaged in a non‐interactive teaching activity. The mere expectation of interactive teaching also produced larger learning effects than the expectation of non‐interactive teaching. These results suggest that preparing‐to‐teach and teaching, interactive teaching after preparing to do so in particular, are useful for enhancing learning. - Japanese Psychological Research, EarlyView.