Background and aims: Our aim in this meta-analysis was to determine the effect of soy and soy product supplementation on serum adiponectin levels. Method: A systematic search was conducted using Medline (PubMed and Web of Science), Scopus, and Cochrane Library for eligible trials up to August 2020. A random-effects model was used to pool calculated effect sizes. Results: Seven trials were included in the overall analysis. Our analysis showed that soy and soy product supplementation did not significantly affect adiponectin concentrations (WMD = −0.77 μg/ml, 95% CI: −0.61, 2.15, P = 0.27) in comparison with a placebo. The between-study heterogeneity was high (I2: 68.2%, P = 0.004). Subgroup analysis, based on participants’ health status and duration of the supplementation, could not detect the potential source of the observed heterogeneity. In addition, subgroup analysis showed that the effect was not statistically significant in all subgroups. Conclusion: Overall, soy and soy product supplementation did not change the circulatory adiponectin levels. In addition, the results were not affected by the participant's health status and duration of supplementation. However, further studies are needed to confirm the present results.