The number of elderly head-and-neck squamous cell carcinoma (HNSCC) patients is increasing; however, the evidence regarding the ideal treatment for this often vulnerable and frail patient cohort is limited. Although the benefit of concomitant chemotherapy has been reported to decrease in elderly HNSCC patients based on the MACH-NC meta-analysis, it remains unknown whether state-of-the art radiotherapy techniques such as intensity-modulated radiotherapy (IMRT), modern supportive treatments and alternative chemotherapy fractionation (e.g., cisplatin weekly) may have altered this observation. The objective of this retrospective multinational multicenter study is to determine the oncological outcomes of elderly patients (≥65 years) with locally advanced HNSCCs undergoing definitive (chemo-)radiation and to investigate the influence of concomitant chemotherapy on overall survival and progression-free survival after adjusting for potential confounder variables such as age, performance status and comorbidity burden.