Background: Several studies have shown that periodontal diseases are associated with hypertension (HT). However, heterogeneity among populations, diagnosis criteria, and shared risk factors represent some difficulties in terms of interpretation. Therefore, the aim of this study was to determine the magnitude of the association between periodontal diseases and HT. Methods and results: A systematic review and meta-analysis, including studies published up to June 2016, have been performed. Sixteen studies assessing the association between periodontal diseases and HT have been included. The meta-analysis considering all included studies (moderate to severe periodontitis) showed that the presence of HT was associated with the presence of periodontal diseases (OR, 1.50; 95% CI, 1.27-1.78). To reduce potential bias, a stratified analysis has been performed illustrating the impact of inclusion criteria and adjustments on the magnitude of the association. Interestingly, when only studies with secure diagnosis of severe periodontitis and HT were considered, an OR=1.64 (95% CI, 1.23-2.19) has been measured. Conclusions: Periodontal diseases are associated with a higher risk of HT especially for severe periodontitis. However, no conclusions could be made regarding the causative involvement of periodontal diseases mainly due to the reduced number of available prospective studies and remaining questions regarding underlying biological mechanisms.