Autistic adults often experience health problems and a range of healthcare barriers. Therefore, the aim of this study was to evaluate barriers and explore how primary care providers and autistic adults want to improve their primary healthcare. Semi-structured interviews with three autistic adults, two parents of autistic children and six care providers, were performed to evaluate barriers in Dutch healthcare. Next, in a three-round Delphi-study, 21 autistic adults and 20 primary care providers rated barriers in primary healthcare and assessed recommendations based on usefulness and feasibility. In the thematically analysed interviews, 20 barriers in Dutch healthcare for autistic people were identified. In the Delphi-study, the primary care providers rated the negative impact of most barriers lower than the autistic adults. The Delphi-study resulted in 22 recommendations to improve primary healthcare for autistic adults, focused on: primary care providers (i.e. education in collaboration with autistic people), autistic adults (i.e. improvement of preparation for general practitioner-appointments) and organization of general practice (i.e. enhancement of continuity in care). In conclusion, primary care providers seem to assess healthcare barriers as less impactful than autistic adults. With the use of the Delphi-method, useful and feasible recommendations to improve primary healthcare for autistic adults were identified, based on the needs of autistic adults and primary care providers.