Résumé : Objectives: The study aimed to investigate the impact of chemoradiotherapy (CRT) on speech and voice quality according to the anatomic localization of the head and neck cancer. Methods: Thirty-four patients treated by CRT for advanced suprahyoid (N = 17) or infrahyoid (N = 17) cancer were assessed for speech function, videolaryngostroboscopy, Voice Handicap Index, blinded Grade, Roughness, Breathiness, Asthenia, Strain, and Instability, acoustic measurements, and aerodynamic measurements. Quality of life was evaluated using the European Organization for Research and Treatment of Cancer Head and Neck 35 (EORTC QLQ-H&N35) questionnaire. Results: Patients treated for an infrahyoid tumor presented more severe values of Voice Handicap Index items, dysphonia, breathiness, asthenia, and some acoustic cues (Voice Turbulence Index, Soft Phonation Index, degree of unvoiced segments, and number of unvoiced segments) than patients treated for a suprahyoid tumor. The EORTC QLQ-H&N35 communication item was better in the suprahyoid patient group. Conclusions: Voice quality impairments associated with CRT are more severe in patients treated for advanced infrahyoid cancer, suggesting the need to develop specific posttherapy management of the dysphonia according to the tumor anatomical localization.