Patients with head and neck squamous cell carcinoma (HNSCC) who have progressed following primary treatment (PT) have a poor prognosis. In this group, nivolumab has been demonstrated to significantly improve outcomes. This study presents the efficacy of nivolumab in Polish patients with recurrent and/or metastatic (R/M) HNSCC using real‐world data. The analyzed group consisted of 324 adult patients with R/M HNSCC following platinum‐based therapy. Patients were divided into 3 groups based on the time from completion of PT to nivolumab initiation (tPT‐N): within 6 months (refractory), between 6 and 24 months (sensitive, tPT‐N ≤24), and beyond 24 months (sensitive, tPT‐N >24). Survival analysis and the Cox proportional hazards model were performed to evaluate how various risk factors affect patient outcomes. The 1‐year and 2‐year overall survival (OS) was 19.1%, 6.1%, 30.7%, 9.4%, and 45.7%, 29.1% in refractory, sensitive tPT‐N ≤24, sensitive tPT‐N >24 patients, respectively and was higher for both sensitivity groups vs. refractory (p = .004) and for sensitive tPT‐N >24 versus refractory and sensitive tPT‐N ≤24 (p <.001). Patients with nasopharyngeal cancer had OS significantly higher than patients with other primary tumor localization. The multivariate Cox analysis showed a significant favorable effect of tPT‐N >24 (HR = 0.53, p = .001) and nasopharyngeal cancer on OS (HR = 0.20, p = .008). Conversely, female sex was identified as an unfavorable factor for OS (HR = 1.48, p = .020). In our study, we established that the benefit of nivolumab increases with the increasing tPT‐N. The probability of death is significantly lower in male patients and patients with nasopharyngeal cancer regardless of tPT‐N.