There is a growing recognition of the need for interventions to improve the healthcare of autistic adults. However, there is a dearth of validated measures to evaluate such interventions. Our objectives were to use a community-based participatory research approach to create an accessible set of patient- and proxy-reported instruments to measure healthcare outcomes and potential intervention targets in autistic adults and to assess the instruments' psychometric characteristics, including content validity, construct validity, and internal consistency reliability. We administered a survey to 244 autistic adults recruited from 12 primary care clinics in Oregon and California, USA (194 participating directly and 50 participating via a proxy reporter). Community partners ensured items were easy to understand and captured the intended construct. The Academic Autism Spectrum Partnership in Research and Education (AASPIRE) Visit Preparedness Scale, Healthcare Accommodations Scale, and Patient--Provider Communication Scale were each found to have a single factor. The AASPIRE Health and Healthcare Self-Efficacy Scale had two factors: Individual Healthcare Self-Efficacy and Relationship-Dependent Healthcare Self-Efficacy. Both patient- and proxy-reported versions of all scales had good to excellent internal consistency reliability, with alphas ranging from 0.81 to 0.96. The scales were associated with the Barriers to Healthcare Checklist and the Unmet Healthcare Needs Checklist in the hypothesized directions.