Purpose To analyze the quality of life (QOL) and performance status (PS) (secondary outcome) in patients with stage III to IV head and neck cancer (HNC) enrolled on a prospective randomized phase 3 trial comparing radiation-cisplatin without cetuximab (CIS) or with cetuximab (CET/CIS). The QOL hypothesis proposed a between-arm difference in Functional Assessment of Cancer Therapy-Head and Neck (FACT-HN) total score of ≥10% of the instrument range from baseline to 1 year. Methods and Materials Patients who gave consent to the QOL/PS study completed the FACT-HN, Performance Status Scale for HNC (PSS-HN), and EuroQol (EQ-5D) at baseline through to 5 years. The pretreatment QOL/PS scores were correlated with outcome and p16 status in patients with oropharyngeal cancer (OPC). Results Of 818 analyzable patients, the 1-year change from baseline score for FACT-HN total was −0.41 (CIS arm) and −5.11 (CET/CIS arm) (P=.016), representing a 3.2% between-arm change of the FACT-HN total score. The mean EQ-5D index and PSS-HN scores were not significantly different between arms. The p16-positive OPC patients had significantly higher baseline and 1-year scores for PSS-HN, FACT-HN total, physical and functional subscales, and 2-years for the EQ-5D index compared with p16-negative OPC patients. Higher pretreatment PSS-HN diet, PSS-HN eating, FACT-HN, and EQ-5D index scores were associated with better overall survival (OS) and progression-free (PFS) survival on multivariate analysis. Higher baseline FACT-HN total, functional, physical subscale, and EQ-5D index scores were associated with improved OS and PFS in p16-positive OPC patients but not in p16-negative and non-OPC patients. Conclusion There was no clinically meaningful difference in QOL/PS between arms. The p16-positive OPC patients had significantly higher QOL/PS than did p16-negative patients. Pretreatment QOL/PS is a significant independent predictor of outcome in locally advanced HNC.