Blended learning, as an approach that combines face-to-face education with online learning, has attracted much attention in recent years. This meta-analysis study was conducted with the aim of investigating the effect of blended learning on the academic progress and motivation of secondary school students. After a comprehensive search of scientific databases and application of inclusion and exclusion criteria, 35 studies with a total of 4,827 participants were selected for the final analysis. The results showed that blended learning has a positive and significant effect on academic achievement (g = 0.68, 95% CI [0.52, 0.84], p < .001) and academic motivation (g = 0.55, 95% CI [0.41, 0.69], p < .001) has students. The analysis of moderators showed that factors such as the ratio of online to face-to-face training time, the type of lesson, and the duration of the intervention moderate the effectiveness of blended learning. These findings provide strong evidence for the effectiveness of blended learning in secondary education and provide suggestions for the effective design and implementation of this approach.