Many studies have identified differences in the effectiveness of the integration of blended learning and project-based learning (BPjBL) models on student achievement. However, the results of previous studies showed different results. Therefore, this study aims to determine the differences in the effectiveness of the integration of blended learning and project-based learning (BPjBL) models on student achievement, compared to traditional learning. The design used in this study was a contrast group meta-analysis. The studies analyzed to calculate the effect size were 11 primary studies that met the established inclusion criteria. To be more accurate, data analysis was performed with the help of JASP software version 0.16.3. The results of the analysis using the random effects approach obtained an overall effect size (d = 1.28; p <0.05). This effect size is included in the large effect category. It can be concluded that the use of the BPjBL model has a major effect on student achievement when compared to traditional learning. The meta-analysis in this study has no problem with publication bias, so this meta-analytic research is objective and scientifically justifiable. The results of this meta-analysis research show more accurate information, which can be used as a basis for policymaking, so as to improve the quality of learning.