The present study aimed to measure the impact of oral health on the quality of life of patients with head and neck cancer. A cross-sectional study was conducted with 130 patients diagnosed with head and neck cancer at two medical centers. Participants answered a sociodemographic questionnaire and the Oral Health Impact Profile - 14 (OHIP-14). Clinical aspects, cancer staging, and treatment approach were also investigated. Mann-Whitney and Kruskal-Wallis non-parametric tests were used for statistical analysis, followed by Poisson regression analysis (with robust error variance), to associate the OHIP-14 scores with independent variables. The OHIP-14 presented good internal consistency (Cronbach?s Alpha = 0.861). The mean score obtained was 19.52 (±11.79). Physical pain (3.70±2.44), physical disability (3.26±2.62) and functional limitation (3.24±2.45) were ranked as the main factors affecting the quality of life. Patients non-Caucasians (PR = 1.30; IC 95% = 1.07-1.58; p = 0.009), widowers (PR = 1.36; IC 95% = 1.13-1.64; p = 0.001), diagnosed with squamous cell carcinoma (PR = 1.28; IC 95% = 1.05-1.58; p = 0.017) and with temporomandibular pain (PR = 1.31; IC 95% = 1.08-1.60; p = 0.007) were more likely to exhibit lower rates of quality of life. The results showed a high impact of the oral health in the quality of life of patients with head and neck cancer was observed. Sociodemographic and clinical characteristics can exert influence on the quality of life of patients with head and neck cancer.