INTRODUCTION: The aim of this cohort study was to examine health-related quality of life (HRQoL) and symptomatology in patients with pulmonary hypertension (PH) and explore factors that influence its evolution over time. METHODS: A prospective longitudinal multisite cohort study. Participants were recruited from specialist UK PH centres and completed a questionnaire pack at baseline, 6, 12 and 18 months to assess HRQoL (emPHasis-10), dyspnoea, fatigue, sleep, anxiety and depression. RESULTS: 185 patients entered the study at baseline and 126 (68%) completed month 18. At baseline, patients had significant impairment of HRQoL, anxiety, depression, dyspnoea and severe fatigue. No significant changes, apart from a reduction in the Hospital Anxiety and Depression Scale-Anxiety score (P=0.04), were observed over 18 months. Depression and dyspnoea were predictors of HRQoL (P=0.002 and P=0.03, respectively). Oxygen use was also associated with diminished HRQoL and increased symptom severity. CONCLUSION: Patients with PH experience high levels of symptom severity and the negative impact on HRQoL was unchanged over time. The use of oxygen therapy, in particular, was associated with a significant impact on HRQoL. Further study of factors impacting HRQoL and interventions that target a combination of physiological and psychosocial consequences of living with PH are needed.