Surgical Site Infection (SSI) is one of the common postoperative complications after gastric cancer surgery. Previous studies have explored the risk factors (such as age, diabetes, anaemia and ASA score) for SSI in patients with gastric cancer. However, there are large differences in the research results, and the correlation coefficients of different research results are quite different. We aim to investigate the risk factors of surgical site infection in patients with gastric cancer. We queried four English databases (PubMed, Embase, Web of Science and the Cochrane Library) and four Chinese databases (China National Knowledge Infrastructure, Chinese Biological Medicine Database, Wanfang Database and Chinese Scientific Journal Database (VIP Database)) to identify published literature related to risk factors for surgical site infection in patients with gastric cancer. Rev Man 5.4 and Stata 15.0 were used in this meta-analysis. A total of 15 articles (n = 6206) were included in this analysis. The following risk factors were found to be significantly associated with surgical site infection in gastric cancer: male (OR = 1.28, 95% CI [1.06, 1.55]), age >60 (OR = 2.75, 95% CI [1.65, 4.57]), smoking (OR = 1.99, 95% CI [1.46, 2.73]), diabetes (OR = 2.03, 95% CI [1.59, 2.61]), anaemia (OR = 4.72, 95% CI [1.66, 13.40]), preoperative obstruction (OR = 3.07, 95% CI [1.80, 5.23]), TNM >= III (OR = 2.05, 95% CI [1.56, 2.70]), hypoproteinemia (OR = 3.05, 95% CI [2.08, 4.49]), operation time >= 3 h (OR = 8.33, 95% CI [3.81, 18.20]), laparotomy (OR = 2.18, 95% CI [1.61, 2.94]) and blood transfusion (OR = 1.44, 95% CI [1.01, 2.06]). This meta-analysis showed that male, age >60, smoking, diabetes, anaemia, preoperative obstruction, TNM >= III, hypoproteinemia, operation time >= 3 h, open surgery and blood transfusion were the risk factors for SSI in patients with gastric cancer.