ObjectivesThis systematic review and meta‐analysis aimed to evaluate the diagnostic ability and examine the efficacy of countermeasures to adverse events of mucosal incision‐assisted biopsy (MIAB) for gastric subepithelial tumors (SETs).MethodsWe performed a literature search and identified 533 relevant articles. Eleven articles, including 339 lesions, were ultimately used in the meta‐analysis. The primary end‐point was the pathological diagnostic rate of MIAB for gastric SETs, and the secondary end‐point was the incidence of adverse events. The efficacy of acid secretion inhibitors in preventing postoperative bleeding and that of local injection before incision to prevent perforation were also examined.ResultsNine studies were conducted in Japan and two in South Korea, of which only two were prospective studies. The pooled pathological diagnostic rate of MIAB for gastric SETs was 87.8% (95% confidence interval [CI] 80.2–94.0; I2 = 68.7%). The adverse event rate of the pooled population was 0.2% (95% CI 0–1.4; I2 = 0%). The acid secretion inhibitors significantly reduced postoperative bleeding (odds ratio 0.06, 95% CI 0.01–0.66, P = 0.02). Perforation occurred in 0% and 2.6% of the local and nonlocal injection cohorts, respectively, and the pathological diagnostic rates were 50% and 66.7%, respectively.ConclusionsMIAB is a reliable technique with a favorable diagnostic rate and few adverse events. Acid secretion inhibitors may effectively prevent postoperative bleeding; however, the efficacy of local injection remains unclear. This technique could be an option for tissue sampling in gastric SETs.