This study investigated the potential benefit of small-group learning on transfer performance using the method of meta-analysis. Results showed positive support for the hypothesis that small-group learning can increase students' transfer performance (average effect size of 0.30). Unlike reviews of effects of cooperation on learning, this review of effects on transfer found no greater benefit of structured small-groups compared to unstructured. This finding, in conjunction with the significant variability found across effect sizes, suggests that further investigation into features of effective unstructured small-group tasks might yield heuristics that teachers could eventually use to make decisions about when collaboration would be most useful. Although some of the reviewed studies were published decades ago, the vast majority were published within the last few years, suggesting a growing area of research interest.