Diet plays a role in the onset and progression of metabolic disorders, including metabolic syndrome (MetS). We aimed to systematically review and conduct a quantitative meta-analysis of results from observational cross-sectional and prospective cohort studies on adherence to the Mediterranean dietary pattern and risk of MetS. Literature databases including PubMed, SCOPUS and EMBASE were searched from the beginning to May 2016. Eight cross-sectional and four prospective studies were included in this meta-analysis, accounting for a total of 33,847 individuals and 6342 cases of MetS. High adherence to the Mediterranean diet was associated with a risk of MetS (RR: 0.81, 95%CI: 0.71, 0.92). Regarding individual components of the MetS, the inverse associations were significant for waist circumference, blood pressure and low HDL-C levels. In conclusion, adoption of a Mediterranean dietary pattern was associated with lower risk of the MetS and it can be proposed for the primary prevention of the MetS.