Background Nasopharyngeal carcinoma (NPC) remains a major oncologic challenge in Indonesia, where most patients present with locoregionally advanced disease. Although chemoradiotherapy is the standard treatment, response varies substantially among patients. Ferritin, an acute-phase reactant involved in iron metabolism, has been associated with tumor progression and systemic inflammation in several malignancies. This study evaluated the relationship between pre-treatment serum ferritin levels and treatment response in NPC patients. Methods A descriptive-analytic study was performed in NPC patients treated at RSUP Dr. M. Djamil Padang. Serum ferritin levels were measured before treatment initiation. Treatment response was assessed after completion of therapy using Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Clinical characteristics including age, sex, TNM stage, and histopathology were documented. Results Twenty-six patients were included, with most presenting at stage III–IV disease. Elevated pre-treatment ferritin levels were identified in 53.8% of patients, with a median value of 304.36 ng/mL (range 43.88–1,595 ng/mL). Following treatment, complete response was observed in 30.8%, partial response in 57.7%, and progressive disease in 11.5%. Patients with progressive disease demonstrated markedly higher ferritin levels compared with those achieving complete or partial response, suggesting an association between increased ferritin and poorer therapeutic response. Conclusion Higher pre-treatment serum ferritin levels may be associated with less favorable treatment response in NPC patients. Serum ferritin may represent a readily available adjunctive biomarker for risk stratification in NPC. Larger prospective studies are needed to confirm its prognostic utility.