There is an increasing awareness of personalized nutrition on glycemic control. This review aimed to assess the effect of diet on gut microbiota and glycemic control among patients with type 2 diabetes. PubMed, Medline, and Google Scholar were searched for relevant articles; the keywords gut microbiota, gut microbiome, prebiotics, probiotics, fiber diet, fasting plasma glucose (FPG), postprandial plasma glucose, the glycated hemoglobin, and HbA1c were used. From among the retrieved studies, 40 full texts were screened and only 17 fulfilled the inclusion and exclusion criteria, and the extraction sheet was used to report the author's names, year of publication, country, number of patients, and the duration of the study. The meta-analysis showed the significant effect of probiotics on reducing HOMA-IR, standardized mean difference (SMD), –0.35; CI –0.68 to –0.02, P=0.04; I 2 = 21%; P=0.28 for heterogeneity, and fasting insulin, (SMD), -8.0; CI, -10.05 to- 5.96; P <0.00001. The included studies showed 82.0% heterogeneity, P=(0.0002), FPG, (SMD), -2.78; confidence interval (CI), -9.49 to 3.92, P=0.42; I 2 = 77%; P=0.0002 for heterogeneity), and gut microbiota, (SMD), 0.49; confidence interval (CI), 0.27 to 0.91, P = 0.02; I 2 = 0.0%; P=1.00 for heterogeneity). However, no effects were observed regarding HbA1c levels, (SMD), 0.50; confidence interval (CI), –16 to 1.16, P = 0.14; I 2 = 89%; P <0.0001 (for heterogeneity), Lactobacillales and Bifidobacterium were associated with good outcomes, while Firmicutes were linked to poor glycemic control. Conclusion: Diet positively affected microbiota diversity, FPG, and insulin resistance; no effects were evident regarding HbA1c.