Background: To investigate the comparative effects of Renin-Angiotensin System (RAS) Blockades and other antihypertensive agents on insulin sensitivity, metabolic cytokines and glycemic control in non-diabetic patients. Methods: We searched for the relevant articles published on MEDLINE, EMBASE, Cochrane Library and Web of Science. 29 randomized control trials that investigated the use of Angiotensin-converting enzyme inhibitors (ACEI) or Angiotensin receptor blockers (ARB) versus active comparator or placebo to determine the effects on insulin sensitivity and glycemic index in non-diabetics were included. Subgroup and meta-regression analyses were performed to explore potential sources of heterogeneity. Results: RAS Blockades significantly decreased the homeostasis model assessment of insulin resistance and fasting plasma glucose (WMD −0.69, 95% CI −1.01 to −0.38, p < 0.001; WMD −0.09 mmol/L, 95% CI −0.15 to −0.03, p = 0.003, respectively), while increased the quantitative insulin sensitivity check index (WMD 0.02, 95% CI 0.01 to 0.03, p < 0.001) among non-diabetic patients. Besides, RAS Blockades significantly decreased hsCRP and TNF-α (WMD −0.41 mg/L, 95% CI −0.70 to −0.11, p = 0.007; WMD −0.21 ng/mL, 95% CI −0.30 to −0.13, p < 0.001, respectively), while increased adiponectin and potassium (WMD 0.46 μg/mL, 95% CI 0.14 to 0.78, p = 0.005; WMD 0.24 mmol/l, 95% CI 0.10 to 0.39, p = 0.001, respectively). Conclusions: RAS Blockades are superior to other antihypertensive agents in improving insulin sensitivity, glycemic control and some metabolic cytokines in non-diabetic patients, indicating a better antihypertensive choice, which probably delays the onsets of diabetes.