Obstructive sleep apnea is a common disorder caused by complete or partial obstruction of the upper airway. It causes symptoms like unexplained day time drowsiness, morning headaches and trouble concentrating among others. Periodontal disease is an inflammatory disease involving the periodontium. It may contribute to systemic inflammatory disease by increasing the production of inflammatory mediators. The relationship between periodontitis and systemic diseases have been investigated with conflicting results. Risk factors for periodontal disease like aging, smoking, drinking, obesity and diabetes are similar to the risk factors for obstructive sleep apnea. Both of these have been associated with systemic inflammation. It is possible that the shared inflammatory pathways and the common risk factors for both obstructive sleep apnea and periodontitis explains the association. In this review article we are exploring the relationship between sleep apnea and periodontitis.