The EuroQol Health and Wellbeing Short Version (EQ-HWB-S) instrument has been developed to measure the health and wellbeing of care-recipients and their caregivers for use in economic evaluation.The EQ-HWB-S has nine items, and pilot UK preference weights have now been developed. We aimed to investigate the validity of the instrument in parents of children with and without health conditions. EQ-HWB-S data were sourced from an Australian paediatric multi-instrument comparison study. We analysed the baseline characteristics and response distribution of the EQ-HWB-S items. Assessment of known-group validity was conducted for EQ-HWB-S items, level sum-scores and preference-weighted scores, including partial effects. Known-group analyses included three child health variables and where caregivers reported coronavirus disease 2019 (COVID-19) had impacted their wellbeing. We included analyses across gender, controlled for child and parent demographic variables, and compared scores across child health conditions. Item responses were distributed as expected, with higher skew for mobility and activities. Parents experienced high levels of exhaustion. We detected significant differences between groups for level sum-scores and preference-weighted scores, as hypothesised; all tests were significant (p < 0.001), with moderate effect sizes (effect sizes were slightly higher for female than male parents). The regression analysis identified significantly different EQ-HWB-S scores for child health samples compared with the general population after controlling for demographic variables. Differences were observed between child health conditions. The EQ-HWB-S is a useful instrument to measure parent quality of life for economic evaluation in this population. Data were limited to one time point; further research should investigate the instrument's sensitivity to change and test-retest reliability in this population.