BACKGROUND AND AIMS: People with inflammatory bowel disease (IBD) often experience pain, fatigue and bowel incontinence and are at an increased risk of anxiety and depression. Our aim was to assess the impact of these symptoms on health-related quality of life (QoL) in IBD. METHODS: In the IBD-BOOST survey, over 26,000 people with IBD across the UK were approached; 8486 participant-completed surveys were returned. Participants' QoL was measured using the EQ-5D-5L questionnaire and their QoL was calculated on a scale ranging from 1 (perfect health) to -0.594 (worst health). Item non-response was imputed. Stages of linear regression models assessed the associations of symptoms with QoL controlling for IBD type, socio-demographic characteristics, co-morbidities and, in further analysis, for IBD activity and IBD control. RESULTS: The EQ-5D-5L questionnaire was fully completed by 8093 (95.4%) participants (mean age of 50 years [SD 15]; 49% with Crohn's disease). The mean QoL was 0.76 (SD 0.23). From the three IBD-related symptoms, pain was associated with the largest QoL decrement (-0.159), followed by fatigue (-0.140) and bowel incontinence (-0.048). Co-occurrence of pain and fatigue further reduced QoL. Clear graded associations were observed between symptom severity and QoL decrements (all trend p < 0.001). Depression and anxiety were also associated with significant QoL decrements (-0.102 and -0.110 for moderate-to-severe anxiety and moderately severe depression, respectively). Worse IBD control and higher IBD activity were associated with lower QoL. CONCLUSIONS: We report strong associations between symptoms of pain, fatigue, bowel incontinence, anxiety, depression, and their severity and reduced QoL in IBD. These estimates could inform future IBD management interventions.