Background Chronic rhinosinusitis (CRS) significantly affects health-related quality of life (HRQoL). Few multinational observational studies have evaluated the impact of CRS with nasal polyps (CRSwNP) on patients' HRQoL. This study aimed to assess HRQoL outcomes (including analyses by disease severity and impact of comorbidities and refractory disease) in CRSwNP patients from a large European database. Methodology: Data were analysed from the Global Allergy and Asthma European Network (GALEN) Rhinosinusitis Cohort, including sociodemographic data, patient-reported disease severity (visual analogue scale), and scores on the 36-Item Short-Form Health Survey (SF-36) questionnaire. Differences in mean SF-36 scores were evaluated between patients with CRSwNP and population norms and between subgroups of interest (disease severity, comorbidity, and refractory disease, defined by a history of sinonasal surgery). Results: Patients with CRSwNP (N = 445) had significantly lower mean SF-36 Physical Component Summary (PCS) and Mental Component Summary (MCS) scores vs population norms, demonstrating that CRSwNP negatively affects HRQoL. The presence of comorbidities affected HRQoL, as shown by significant differences in PCS scores in patients with asthma or non-steroidal anti-inflammatory drug-exacerbated respiratory disease, compared with patients without asthma. Patients with moderate-to-severe disease had significantly lower PCS scores than patients with mild disease. Severe disease had a significant impact on MCS score. History of surgery had a clinically meaningful negative effect on HRQoL compared with no history of surgery. Conclusions: CRSwNP patients have significantly lower HRQoL compared with population norms. The impact is greater in patients with greater disease severity, comorbidities, or refractory disease.