Objectives: Several risk factors have been recognized in the progress of coronavirus disease 2019 (COVID-19) toward a severe stage. Poor oral health has been relevant to many systemic diseases due to higher inflammation. This study sought to aim the influence of oral health status on severe COVID-19. Methods: A systematic search of the medical literature was done using a combination of search terms of online databases including PubMed/Medline, Medline, SCOPUS, Ovid, Cochrane database, and Google Scholar from December 1st, 2019 to July 30th, 2021. Only articles written in the English language were selected. Results: A total of 352 studies were reviewed for relevance, specified by the title, abstract, and full copy leading to a yield of 25 articles satisfying inclusion criteria. COVID-19 patients with poor oral health status were at a higher risk of intensive care unit (ICU) hospitalization, need for mechanical ventilation, first and second-week deterioration, delayed recovery period, and mortality. Predisposing individuals to serious systemic diseases, conducting pathogens to the lower airways, developing bacterial co-infection, impairing the function of the innate immune system, increasing expression of angiotensin-converting enzyme-II (ACEII) receptors, and enhancing expression of inflammatory cytokines are oral-related risk factors for severe COVID-19 infection. Conclusions: This systematic literature review presents that poor oral health status is linked to severe COVID-19 complications. Monitoring and maintaining oral health, identifying risk groups, and developing appropriate recommendations are simple strategies to combat the current coronavirus crisis.