BackgroundThis study aimed to investigate the relationship between the pan‐immune‐inflammation value (PIV) and periodontitis based on a large national survey.MethodsIn the present cross‐sectional study, data were obtained from the National Health and Nutrition Examination Survey (NHANES) 2009–2014, which included a total of 10,300 participants. The categorization of periodontitis was based on the 2017 classification scheme. The PIV was determined using the formula: (neutrophils count × monocyte count × platelet count)/lymphocytes count. Restricted cubic spline and weighted multivariable logistic regression analyses were employed to evaluate the associations between the PIV with periodontitis.ResultsThe associations between PIV and stage III/IV periodontitis followed a U‐shaped pattern (Pnon‐linearity < 0.001). The risk of developing stage III/IV periodontitis showed an increasing trend among participants in the first quartile (odds ratio [OR] = 1.21; 95% confidence interval [CI]: 1.01–1.46), third quartile (OR = 1.34; 95% CI: 1.11–1.61), and fourth quartile (OR = 1.47; 95% CI: 1.25–1.73) compared to those in the second quartile. Subgroup analysis indicated stronger associations of PIV with periodontitis in males (ORQ4vs2 = 1.72, 95% CI: 1.36–2.18) and individuals with hypertension (ORQ4vs2 = 1.78, 95% CI: 1.38–2.28) with significant interactions (Pinteraction < 0.05).ConclusionsThere is a U‐shaped association between PIV and stage III/IV periodontitis, which suggests a potential adjunctive treatment strategy for periodontitis. Higher PIV values were found to have a stronger correlation with stage III/IV periodontitis in males and individuals with hypertension. Further prospective trials are needed to confirm the validity of our results.Plain Language SummaryA U‐shaped association exists between the pan‐immune inflammation value and periodontitis in US adults, suggesting that maintaining a moderate immune inflammation response is crucial for periodontal health.