Overlearning is defined as the continued study of an item immediately after it has been correctly recalled once. Based on past studies, the effectiveness of overlearning is uncertain. In the present study, the effectiveness of overlearning was tested in 3 experiments. In Experiment 1, participants studied 10 city-country pairs (e.g. doba, chad) to either a low or high degree of learning and were tested 1, 3, or 9 weeks later. In Experiments 2 and 3, participants studied varying numbers of word-definition pairs (e.g. vizard, mask) for a constant total study time. They were tested between 1 and 4 weeks later. While overlearning improved test performance, this difference in recall diminished at longer retention intervals. Furthermore, overlearning was found to be inefficient because the increase in recall was not proportional to the increase in study time. Finally, for a given amount of study time, the underlearning of more words led to higher absolute recall totals than did the overlearning of fewer words.