Vegetables and fruits have been recommended to diabetes patients to control blood glucose. Vegetarian diet is one of options for patients with diabetes. This paper aimed to examine the role of vegetarian diets in improving glycemic control, metabolic parameters, and body weight among patients with type 2 diabetes. Digital archives including MEDLINE, CINAHL, CENTRAL databases and hand searches from 1980 to 2013 were performed. Studies are eligible in case of randomized controlled trials [RCTs] with vegetarian diets as an intervention among patients with type 2 diabetes, as well as outcomes including glycemic control, metabolic parameters, and body weight. Meta-analyses were conducted using RevMan 5. Nine hundred eighty three potentially articles were identified from initial search. After removing illegible studies, five studies were included in the systematic review. Yet, only three studies were included in meta-analysis. The vegetarian diets had a significant effect on all of parameters, except fasting plasma glucose that is in borderline. The HbA1c was decreased on 0.20. On the metabolic parameters i.e. cholesterol, triglycerides, HDL, and LDL were declined to 0.17, 0.28, 0.13, and 0.10, respectively. Body weight was reduced approximately 1.41 among type 2 diabetes patients those consuming vegetarian diet. Vegetarian diets have significant benefits in improving glycemic index, metabolic parameters, as well as body weight. These findings suggest that vegetarian diets could be an option among diabetes patients, since it is beneficial on glycemic control, metabolic parameters, and weight loss.