Induction refers to the process in which people generalize their previous experience when making uncertain inferences about the environment that go beyond direct experience. Here we show that interim tests strongly enhance inductive learning. Participants studied the painting styles of eight famous artists across four lists, each comprising paintings by one pair of artists. In an interim test group participants’ induction was tested after each list. In two control groups participants solved math problems (interim math group) or studied additional new paintings (interim study group) following each of Lists 1–3 and were asked to classify new paintings on List 4. In the List 4 interim test, the interim test group significantly outperformed the other two groups, indicating that interim testing enhances new inductive learning. In a final cumulative test, accuracy in the interim test group at classifying new paintings by studied artists was nearly double that of the other two groups, indicating the major importance of interim testing in inductive learning. This enhancing effect of interim testing on inductive learning was associated with metacognitive awareness.