We examined the association between states' legislative mandates that private insurance cover autism services and the health care-related financial burden reported by families of children with autism. Child and family data were drawn from the National Survey of Children with Special Health Care Needs (N  =  2,082 children with autism). State policy characteristics were taken from public sources. The 3 outcomes were whether a family had any out-of-pocket health care expenditures during the past year for their child with autism, the expenditure amount, and expenditures as a proportion of family income. We modeled the association between states' autism service mandates and families' financial burden, adjusting for child-, family-, and state-level characteristics. Overall, 78% of families with a child with autism reported having any health care expenditures for their child for the prior 12 months. Among these families, 54% reported expenditures of more than $500, with 34% spending more than 3% of their income. Families living in states that enacted legislation mandating coverage of autism services were 28% less likely to report spending more than $500 for their children's health care costs, net of child and family characteristics. Families living in states that enacted parity legislation mandating coverage of autism services were 29% less likely to report spending more than $500 for their children's health care costs, net of child and family characteristics. This study offers preliminary evidence in support of advocates' arguments that requiring private insurers to cover autism services will reduce families' financial burdens associated with their children's health care expenses.