Both asthma and periodontitis are multifactorial highly prevalent with global burden chronic diseases sharing similar genetic, environmental, infectious and inflammatory factors. The first attempts to study the relationship between asthma and periodontal diseases started in the 1970s and continued till nowadays, to this date no direct causality had been proven between periodontal diseases and asthma, but a strong body of evidence supports a strong positive association between them, although many studies found a positive association between asthma and periodontitis, on the opposite direction many studies did find an inverse type of relationship, and some studies did not find any sort of association which refer to the diverging finding in the literature regarding asthma and periodontitis, these conflicting results may be attributed to the shared risk factors and to the lack of standardizations in defining periodontal diseases and asthma leading to inconsistent results in different studies, we did this literature review to systematically revisit the current evidence concerning the complicated and often conflicting researches studying the link between asthma and periodontitis.