Abstract Background It is unknown whether weight class is associated with impairment of health-related quality of life (HRQOL) for children in the Netherlands. The aim of this study was to explore generic and weight-specific HRQOL in a clinical cohort of children with overweight, obesity or severe obesity aged 5–19 years in the Netherlands. Methods 803 children from three clinical cohorts participated: mean age 11.5 (SD 2.9) years, 61.1% girls. The influence of weight class was explored in a subgroup of 425 children (25.2% with overweight, 32.5% obesity and 42.3% severe obesity), of whom the exact International Obesity Task Force (IOTF) BMI class was known. Generic HRQOL was measured by the PedsQL child report. Weight-specific HRQOL was measured by the IWQOL-Kids child or parent report. Average total, subscale and item scores were reported and the influence of the IOTF BMI class analyzed by multiple linear regression, corrected for age and sex. Results Children with severe obesity had lower generic and ...