Background: Children with autism spectrum disorder (ASD) experience a range of severity levels characterised as levels of support they need for everyday functioning. By this definition, greater levels of severity should warrant greater use of services and supports among children with ASD. In previous studies, Latino children with ASD in the USA have been shown to have lower access to diagnosis and treatment services than White children. However, none have examined service use in relation to severity. In this study, we examined whether there are ethnic disparities between Latino and White children with ASD in specialty autism-related services, and whether functional severity moderates the relationship between ethnicity and receipt of autism services. Methods: We used data from the Survey of Pathways to Diagnosis and Services, a supplement to the National Survey of Children with Special Health Care Needs and analysed four specialty services commonly used by children with ASD, adjusting for demographic variables. Results: We found that Latino children with ASD who had severe limitations received fewer specialty autism-related services than White children with similarly severe conditions. These disparities were evident despite the fact that the sample of Latino children in these data were more privileged than the general US Latino population. Conclusion: Assertive policy initiatives are needed to address these disparities and ensure that these highly vulnerable children with severe functional limitations receive appropriate services and supports.