Background Chemoradiation with curative intent in older adults with locally advanced head and neck squamous cell carcinoma (HNSCC) has been a challenge, because of its potential toxicities. Methods We selected primary HNSCC cases from the SEER‐Medicare linked database, assessed overall survival (OS) and adverse events and their associations with different treatments, across four age groups including the youngest (66–69 years) and the oldest (≥80 years). Results Better OS was associated with chemoradiation compared to radiation alone, not only in all patients (N = 5879) (hazard ratio HR = 0.82, p < 0.001), but also in the oldest group (N = 1380) (HR = 0.77, p = 0.006) in whom the adverse events rates were not higher than those in the youngest (N = 1562); more of the latter (26%–30%) than the former (14%–19%) received chemoradiation, regardless of their comorbidity indices. Conclusions Our findings provide evidence that patients' characteristics, other than chronological age, should be equally considered in selecting the best therapy for older patients with HNSCC.