Periodontitis, a chronic inflammatory disease caused by plaque biofilm, is characterized by the irreversible pathological destruction of periodontal supporting tissues, including gums, periodontal membranes, alveolar bone, and cementum, resulting in tooth loosening and dislocation in severe cases. Currently, research on the pathogenesis, early diagnosis, and treatment of periodontitis is limited. Circular RNAs (circRNAs), previously considered “splicing noise”, have gained increasing research attention with the development of high-throughput sequencing technologies and bioinformatics. CircRNAs are non-coding RNAs lacking a 5' cap and 3' poly(A) tail, with a unique covalently closed ring structure, high expression, long half-life, and resistance to nuclease degradation, which can regulate splicing, encode proteins, and act as microRNA and RNA-binding protein sponges. In recent years, circRNAs have been reported to be involved in the occurrence and development of periodontitis, suggesting its potential role as a therapeutic target for periodontitis treatment. In this study, we described the biological function of circRNAs and their role in the development of periodontitis and the regulation of periodontal homeostasis and immune microenvironment. We found that circRNAs affect periodontal homeostasis and immune microenvironment by regulating the apoptosis of periodontal tissue cells (such as periodontal ligament stem cells and gingival fibroblasts) and regulating immune cells or cytokines, respectively. This review article summarizes the latest research progress on the association between circRNAs and periodontitis to provide a scientific basis for the development of novel diagnostic, therapeutic, and prognostic strategies for periodontitis.