According to previous studies of obesity, we found that the association between homocysteine concentrations and obesity was reported controversially. Thus, we carried out this meta-analysis to investigate this association. We searched PubMed, Cochrane library, and EMBASE database for studies that evaluate the relationship between homocysteine concentrations and obesity from inception to March, 2019. The quality of all included studies was assessed by the Newcastle Ottawa Scale (NOS) and the Agency for Healthcare Research Quality (AHRQ). The RevMan5.3 software and Stata12.0 software were used for conducting all date analyses. Standardized mean differences (SMD) with the corresponding 95% confidence intervals (95% CIs) were used as a measure of effect size to assess the relationship between homocysteine concentrations and obesity through a meta-analysis. The level of significance was set at P <.05. A total of 14 studies were ultimately included in our meta-analysis. Meta-analysis of the 14 studies found remarkable lower homocysteine concentrations in controls than in obese patients (SMD = 0.76, 95% CI = 0.25-1.27, P <.01; I2= 94% and P <.01 for heterogeneity), regardless of nutritional status, dietary habit, insulin resistance (IR) status, special disease history, history of medicine taken, genetic background, and so on. Homocysteine concentrations in nonobese patients with polycystic ovarian syndrome (PCOS) were lower than obese patients with PCOS (SMD = 0.48, 95% CI = 0.20-0.77, P <.01; I2= 39% and P =.18 for heterogeneity). The result of our meta-analysis showed that homocysteine concentrations were significantly elevated among obese patients. © 2020 Chinese Cochrane Center, West China Hospital of Sichuan University and John Wiley & Sons Australia, Ltd