Peripheral T-cell lymphoma (PTCL) encompasses a group of rare and aggressive lymphomas. PTCL, unspecified (PTCLU) is the most common subtype of PTCL, and carries a poor prognosis. The International Prognostic Index (IPI) and the Prognostic Index for PTCLU (PIT) scoring systems are powerful risk-stratification tools in patients with PTCL. The aim of this study was to evaluate whether the neutrophil-to-lymphocyte ratio (NLR) is a prognostic factor in PTCLU. We retrospectively studied 83 patients with diagnosis of PTCLU. In the univariate analysis, NLR ≥ 4 was associated with worse overall survival (HR 3.96, 95% CI 1.92-8.17; p < 0.001). In the multivariate analysis, NLR ≥ 4 was independently associated with worse overall survival after adjustment for the PIT score (HR 4.30, 95% CI 1.90-9.69; p < 0.001), and for the IPI score (HR 2.60, 95% CI 1. 12-6.04; p = 0.03). Our study suggests the NLR could be helpful in refining the survival prognostication in patients with PTCLU.