Previous studies have investigated the pretreatment prognostic nutritional index (PNI) as a prognostic factor in patients with nasopharyngeal carcinoma (NPC); however, the results remained inconsistent. We aimed to assess the prognostic value of PNI in patients with NPC through conducting meta-analysis. Methods: Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated for low PNI of overall survival (OS), progression-free survival (PFS), distant metastasis-free survival (DMFS), loco-regional recurrence-free survival (LRFS), and cancer-specific survival (CSS). Results: Totally, eight studies involving 4299 patients were included in this meta-analysis. A low pretreatment PNI was associated with poor OS (HR = 1.86, 95% CI = 1.55-2.33, P < 0.001), DMFS (HR = 2.03, 95% CI = 1.69-2.44, P < 0.001), PFS (HR = 1.57, 95% CI = 1.31-1.90, P < 0.001), and CSS (HR = 2.29, 95% CI = 1.54-3.42, P < 0.001). The subgroup analysis showed that low PNI remained a significant factor for poor OS, DMFS, and PFS irrespective of treatment, country, and cutoff value of PNI. In addition, low PNI was correlated to female gender (OR = 1.35, 95% CI = 1.12-1.62, P = 0.002), older age (OR = 1.75, 95% CI = 1.17-2.62, P = 0.007), and T3-T4 stage (OR = 1.27, 95% CI = 1.06-1.53, P = 0.011). Conclusions: A low PNI was associated with poor survival outcomes in patients with NPC. Moreover, PNI could serve as an index to help guide clinical management for older patients.