Brominated flame retardants (BFRs) are widely utilized to mitigate the flammability of various materials. Previous studies have revealed the impact of BFRs exposure on hormonal disruption and bone metabolism which are closely related to periodontitis. However, it remains unknown the potential relationship between BFRs and periodontitis. This study aimed to explore the association between BFRs exposure and periodontitis in US adults. The data analyzed in this study were obtained from the National Health and Nutrition Examination Survey (NHANES) 2009-2014. Twelve serum BFRs were quantified using isotope dilution gas chromatography high-resolution mass spectrometry. Univariable and multivariable logistic regression was employed to evaluate the association between serum BFRs and periodontitis. Bayesian kernel machine regression (BKMR) analyses were utilized to assess the association between mixtures of BFRs and periodontitis. A total of 3311 eligible participants were included. Serum BFRs (PBDE-47, PBDE-99, and PBDE-154) were significantly associated with periodontitis, and the odds ratios (ORs) and corresponding 95% confidence intervals(CIs) were 1.15(1.01,1.29), 1.10(1.01,1.20), and 1.12(1.01,1.25), respectively. Notably, these three BFRs were also significantly associated with the severity of periodontitis. Additionally, the BKMR model revealed a significant association between the mixture of all twelve BFRs and periodontitis. This preliminary study suggests a significant association between specific serum BFRs (PBDE-47, PBDE-99, and PBDE-154) and periodontitis and its severity. Further prospective and experimental studies are warranted to validate our findings.