The purpose of this research was to conduct a meta-analysis of the studies on the effect of blended learning on academic performance in Iran. The meta-analysis was based on the estimated effect size of blended learning on academic performance. 211 studies were identified in the period 2010-2017, of which 20 research documents were selected using non-probability (purposive) sampling. Initial data analysis was done in SPSS using the PRISMA checklist, and Cohen’s model was used to interpret the results. The results showed that there is a significant positive relationship between blended learning and academic performance. The estimated effect size for this relationship was 0.684, which is higher than the medium level in Cohen’s model (0.5). This indicates the real effects of the blended learning approach on academic performance. Overall, the results showed that the blended learning approach, with proper needs assessment, design, implementation, evaluation, and feedback, can be a logical and flexible strategy for improving academic performance.