Obesity is characterized by the abnormal or excessive deposition of fat in the adipose tissue. Its consequences go far beyond adverse metabolic effects on health, causing an increase in oxidative stress that leads not only to endothelial dysfunction but also to negative effects in relation to periodontitis, because of the increase in proinflammatory cytokines. Thus, obesity appears to participate in the multifactorial phenomenon of causality of periodontitis through the increased production of reactive oxygen species. Within this context, this paper aims to highlight, by analysis and description of previous studies, the interface between obesity and periodontitis, with emphasis on oxidative stress and the inflammatory response.