Background The purpose of this study was to assess the unmet health care needs of children with intellectual disability (ID) compared with children with autism spectrum disorder (ASD) and whether access to health insurance coverage is a contributing factor. Children with ID may be masked in the health care system due to increased diagnosis and awareness of ASD. The needs, unmet needs and insurance coverage of children with ID alone, ASD alone, and co‐occurring ID and ASD were assessed in this study. Methods The 2016 to 2019 United States' Census Bureau National Survey of Children's Health was used to determine differences in unmet needs, care not received and health insurance coverage during the past year for children with ID and/or ASD. Adjusted odds ratios and 95% confidence intervals for care not received were determined controlling for sex, insurance, race, age and parents' highest education level. Results Children with ID were nearly four times more likely not to receive needed medical care as children with ASD. Results were similar for unmet hearing and mental health care. Children with both ID and ASD were more likely to have unmet health care but less likely to have unmet medical care compared with children with ASD alone. There were no significant differences for unmet dental or vision care. Children with ID were 3.58 (95% confidence interval: 1.6–8.0) times more likely to have inconsistent health insurance compared with children with ASD. Conclusions Children with ID alone are more likely to have unmet medical, hearing and mental health care needs than children with ASD alone. Children with co‐occurring ID and ASD have a large amount of general unmet health care needs but less unmet medical needs. Children with ID are less likely to have consistent health insurance than children with ASD. This hinders the ability of children with ID to receive quality care. Further research is needed to determine if the diagnosis of ASD in children in the United States is negatively affecting children with ID alone.