BACKGROUND The aim of this study is to evaluate the gingival crevicular fluid (GCF), saliva, and serum concentrations of tumor necrosis factor-α (TNF-α), TNF-α receptor-1 (TNF-αR1), TNF-αR2, and interleukin-6 (IL-6) in non-obese females with polycystic ovary syndrome (PCOS) and either clinically healthy periodontium or gingivitis. METHODS Thirty-one females with PCOS and healthy periodontium, 30 females with PCOS and gingivitis, and 12 systemically and periodontally healthy females were included in the study. GCF, saliva, and serum samples were collected, and clinical periodontal measurements, body mass index, and Ferriman-Gallwey score (FGS) were recorded. Sex hormones, cortisol, and insulin levels were measured. TNF-α, TNF-αR1, TNF-αR2, and IL-6 were determined by enzyme-linked immunosorbent assay. Kruskal-Wallis followed by Bonferroni-corrected post hoc Mann-Whitney U tests were used to analyze the data. RESULTS The PCOS + gingivitis group revealed significantly higher GCF, saliva, and serum IL-6 concentrations than the PCOS + healthy group (P <0.0001). The two PCOS groups exhibited significantly higher saliva TNF-α concentrations than the control group (P = 0.024 and P = 0.013, respectively). The FGS index was significantly higher in the PCOS + gingivitis group than the PCOS + healthy group (P = 0.030). The PCOS + gingivitis group revealed significantly higher insulin concentration than the PCOS + healthy and control groups (P = 0.014 and P <0.0001, respectively). Serum TNF-α, TNF-αRs, and serum, GCF, and salivary IL-6 levels correlated with the clinical periodontal measurements. CONCLUSIONS PCOS and gingival inflammation appear to act synergistically on the proinflammatory cytokines IL-6 and TNF-α. Thus, PCOS may have an impact on gingival inflammation or vice versa. Additional studies are warranted to clarify the possible relationship between PCOS and periodontal disease.