Autism diagnosis before age three to expedite access to critical services is a public health priority in the United States. Still, the average age of autism diagnosis is 49 months with substantial variability across states. By examining policy--defined as laws, regulations, procedures, administrative actions, incentives, or voluntary practices of governments or other institutions--modifiable structural drivers of early (or late) autism diagnosis may be identified. We, therefore, sought to identify policies impacting early autism diagnosis in five states that are part of a larger initiative to improve autism diagnosis (Arizona, California, Connecticut, Massachusetts, and Pennsylvania) and those that exist nationally. We conducted semi-structured interviews from 2021 to 2023 with a purposive sample of 57 autism policy or research experts. The following four themes were identified through conventional content analysis: (1) developmental monitoring is critical; however, developmental screening policies vary within and across states; (2) myriad policy and contextual factors shape early diagnosis pathways within states; (3) early intervention by the state and community-based early childhood programs influence early autism diagnosis; and (4) persistent disparities in early autism diagnosis pathways are affected by policies. Study findings highlight the importance of advancing certain state and federal policies to increase early autism diagnosis.