BACKGROUND: Previous studies have investigated the prognostic value of the systemic immune-inflammation index (SII) in nasopharyngeal carcinoma (NPC). However, the results have been inconsistent. Therefore, this study aims to investigate the prognostic significance of SII in NPC through a meta-analysis. METHODS: The PubMed, Web of Science, Embase, and Cochrane Library databases were thoroughly searched. The pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated to evaluate the prognostic value of the SII for survival outcomes. RESULTS: A total of six studies comprising 2169 patients were included in the meta-analysis. Pooled analyses indicated that a high SII was significantly associated with worse overall survival (OS) (HR = 1.69, 95% CI = 1.36-2.09, P < 0.001) and progression-free survival (PFS) (HR = 1.60, 95% CI = 1.29-1.98, P < 0.001) in patients with NPC. Subgroup analysis showed that SII was a significant prognostic marker for PFS but not for OS in NPC. CONCLUSION: Our meta-analysis demonstrated that a high SII could be an efficient prognostic indicator of OS and PFS in NPC. In our opinion, SII could be used to predict long-term and short-term outcomes in patients with NPC. Furthermore, we suggest that SII be applied to help individual patients with NPC assess the prognostic risk. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42022321570.