Several findings correlated Covid-19 with oral health status, including periodontal diseases. The disease has mainly been related to the incidence of comorbidities in Covid-19 patients. Periodontal diseases such as chronic peri- odontitis potentially contribute to the severity and mortality. This systematic review and meta-analysis were aimed to overview studies of the relationship between periodontal disease and the severity of Covid-19 (hospitalization). There were nine studies, analyzed in this systematic review (nine reviews and three meta-analyses). The quality assessment of studies was using Newcastle-Ottawa Scale (NOS) and the pooling effect of meta-analysis were using random-effects model. The NOS scores were Satisfied (5-6 stars) for seven studies, meanwhile Good (7 stars) for two studies. The estimated OR was 2.68 (P = 0.006). The heterogeneity (I 2 ) was 61%, showed moderate heterogeneity. Covid-19 and severity depended on the host and viral factors that influence the immune response. The surge of cyto- kines (especially IL-6) was found as an imperative role in the Covid-19 and periodontal diseases. Finally, periodontal diseases were found positively contributed to the severity of Covid-19. Periodontal diseases were found associated with the severity and mortality of Covid-19. However, further studies are a necessity to generalize in other popula- tions of Covid-19 patients.