The main goal was to test if children with intellectual disability (ID) and autism spectrum disorder (ASD) show lower quality of life (QOL) in comparison to those with only ID. The KidsLife Scale was applied to 1060 children with ID, 25% of whom also had ASD, aged 4-21 years old. Those with ASD showed lower scores in several QOL domains but, when the effect of other variables was controlled, lower scores were only kept for interpersonal relationships, social inclusion, and physical wellbeing. Slightly higher scores were found for material wellbeing. ASD, Level of ID and support needs were the covariables with the greatest influence in most domains, while gender was only significant for social inclusion (girls scored lower than boys).