Background The protein encoded by ZBTB20 is a member of the POK family, whose members function as transcriptional repressors through interactions mediated by their conserved C2H2 Krüppel-type zinc finger and BTB/POZ domains. Polymorphisms in ZBTB20 appeared to be associated with gastric and esophageal cancer susceptibility in biological models, but the results of these studies were inconclusive. Therefore, we conducted a meta-analysis by pooling all available data to assess the exact association between the ZBTB20 rs9841504 polymorphism and gastric and esophageal cancer susceptibility. Method The meta-analysis was performed for homozygote comparison, heterozygote comparison, and dominant and recessive models by applying a fixed- or random-effects model. The pooled odds ratios (ORs) with the corresponding confidence intervals (CIs) were calculated. Moreover, the data were analyzed using the Stata 12.0 software(StataCorp). Result A total of 8 independent case-control studies comprising 9,994 cases and 10,258 controls were included. We found a significant association between the rs9841504 polymorphism and decreased gastric cancer susceptibility in the allelic, homozygous, dominant and recessive models (B vs. A:OR = 0.797, 95% CI 0.644-0.986, p = 0.036; BB vs. AA:OR = 0.601, 95% CI 0.366-0.988, p = 0.045; BA + BB vs. AA:OR = 0.789, 95% CI 0.627-0.992, p = 0.043; BB vs. BA + AA:OR = 0.635, 95% CI 0.405-0.997, p = 0.049). Conversely, no association between the rs9841504 polymorphism and esophageal cancer susceptibility was found. In subgroup analysis by ethnicity, we observed a significantly decreased susceptibility to gastric cancer in Asian populations in the allele contrast, homozygous and recessive models (B vs. A:OR = 0.791, 95% CI 0.628-0.996, p = 0.046; BB vs. AA:OR = 0.559, 95% CI 0.323-0.966, p = 0.037; BB vs. BA + AA:OR = 0.593, 95% CI 0.361-0.972, p = 0.038). Conclusions In summary, our work suggests that the ZBTB20 rs9841504 polymorphism is a protective factor for gastric cancer rather than esophageal cancer.