Evidence regarding the effect of isomaltulose on glycemic and insulinemic responses is still conflicting, which limits isomaltulose's application on glycemic management. The purpose of this study was to comprehensively evaluate its effectiveness and evidence quality. We systematically searched PubMed, Embase, and the Cochrane Library for randomized controlled trials (RCTs) prior to October 2021. RCTs were eligible for inclusion if they enrolled adults to orally intake isomaltulose or other carbohydrates dissolved in water after an overnight fasting and compared their 2-hour postprandial glucose and insulin concentrations. DerSimonian-Laird method was used to pool the means of the circulating glucose and insulin concentrations. Both random-effect and fixed-effect models were used to calculate the weight mean difference in postprandial glucose and insulin concentrations in different groups. Subgroup, sensitivity and meta-regression analyses were also conducted. Grading of Recommendations Assessment, Development, and Evaluation was used to assess the certainty of evidence. Finally, 11 RCTs (n = 175 participants) were included. The trials were conducted in four countries (Japan, Brazil, Germany, and the Netherlands), and all the enrolled participants were >18 years of age with various health status (healthy, type 2 diabetes, impaired glucose tolerance, and hypertension). Moderate evidence suggested that oral isomaltulose caused an attenuated glycemic response than sucrose at 30 min. Low evidence suggested that oral isomaltulose caused an attenuated but more prolonged glycemic response than sucrose and an attenuated insulinemic response. Low-to-moderate levels of evidence suggest there may be more benefit of isomaltulose for people with type 2 diabetes, impaired glucose tolerance, or hypertension; older people, overweight or obese people, and Asian people. The study was registered on PROSPERO (International prospective register of systematic reviews) as CRD42021290396.© The Author(s) 2022. Published by Oxford University Press on behalf of the American Society for Nutrition.