This study aims to investigate the association between systemic inflammation, measured by the systemic immune-inflammatory index (SII), and menopausal symptoms in postmenopausal women. A cross-sectional study was conducted with 702 postmenopausal women recruited from a tertiary hospital. Participants completed the Menopause Rating Scale (MRS) to assess somatic, psychological, and urogenital symptoms. Blood samples were collected to calculate SII. Statistical analyses included correlation, univariate regression, and multivariate regression to determine the association between SII and menopausal symptoms. The most commonly reported symptoms were muscle and joint problems (75.9%), hot flashes and sweating (72.5%), sleeping problems (71.2%), and depressive mood (69.9%). Women with higher total and somatic subscale scores had significantly elevated SII levels compared with those with lower scores. SII was the most associated variable for high total MRS (odds ratio, 4.77; 95% CI, 3.36-6.78; P < 0.001) and somatic subscale scores (odds ratio, 6.32; 95% CI, 4.45-8.99; P < 0.001). Exercise and gravidity were negatively associated with high total MRS and somatic subscale scores. Conversely, no significant associations were observed between SII and the urogenital or psychological subscale scores. Elevated SII levels were found associated with higher somatic subscale and total MRS scores, suggesting that inflammation may contribute to worsened somatic menopausal symptoms in this group. These findings suggest that exploring inflammatory pathways could be beneficial in managing menopausal symptoms and enhancing quality of life for postmenopausal women.