Introduction: Obesity and periodontitis are among the most common noncommunicable diseases, and epidemiological studies report the influence of obesity on the onset and progression of periodontitis. Objective: To review the published scientific evidence about the association between overweight / obesity and periodontal disease in the adult population. Methods: A review of the relevant literature in the English language was carried out in the EBSCO, Science Direct, PubMed and Medline databases. The search period included the last ten years. The articles were selected according to the inclusion criteria that considered systematic reviews on the relationship between overweight / obesity and periodontal disease and / or periodontitis, in order to find a relationship between them; later the narrative review explains biologically and physiologically this relationship. Results: Multiple systematic reviews have reported a significant relationship between obesity and periodontal disease in various populations. Some authors have identified that in obesity states there are changes in the pro-inflammatory immune response, impaired glucose tolerance, alterations in lipid profiles, alterations in host immunity and microvascular functions, increased activation of macrophages, secretion of pro-inflammatory substances from adipose tissue including TNF-α, IL-6 and C-reactive protein. Discussion: The scientific evidence about the association between overweight / obesity and periodontal disease is variable, but has a greater tendency towards positive correlation, although some results are inconclusive. Conclusions: There is a positive relationship between the condition of overweight / obesity and the periodontal disease that would transit between several associated systemic conditions. It is recommended to determine the magnitude of the relative contribution of obesity on the appearance of periodontal disease. KEYWORDS: overweight, obesity, periodontitis.