Extranodal nasal-type NK/T-cell lymphoma is rarely observed in children and adolescents. We aim to investigate the clinical features, prognosis, and treatment outcomes in these patients. Thirty-seven patients were reviewed. There were 19, 14, 2, and 2 patients with stage I, stage II, stage III, and stage IV diseases, respectively. Among the patients with stage I and II disease, 19 patients received initial radiotherapy with or without chemotherapy, and 14 patients received chemotherapy followed by radiotherapy. The 4 patients with stage III and IV disease received primary chemotherapy and radiation of the primary tumor. Children and adolescents with extranodal nasal-type NK/T-cell lymphoma usually presented with early-stage disease, high frequency of B symptoms, good performance, low-risk age-adjusted international prognostic index, and chemoresistance. The complete response rate after initial radiotherapy was 73.7%, which was significantly higher than the response rate after initial chemotherapy (16.7%) (p = 0.002). The 5-year overall survival (OS) and progression-free survival (PFS) rates for all the patients were 77.0% and 68.5%, respectively. The corresponding OS and PFS rates for patients with stage I and II disease were 77.6% and 72.3%, respectively. Children and adolescents with early-stage extranodal nasal-type NK/T-cell lymphoma treated with primary radiotherapy had a favorable prognosis.