<p>Autism is commonly associated with younger people, however, more adults in middle-to-later life are seeking diagnosis despite research being significantly underrepresented in this group. Therefore, a thematic synthesis of qualitative studies was carried out, specifically to explore the experiences of being Autistic in middle-to-later life. Searches across online databases resulted in 3,063 individual studies with fourteen meeting final inclusion for synthesis. Relevant data were extracted, and quality of studies appraised. Four analytical themes were developed. Middle-to-older Autistic adults were likely to experience marginalisation, impacting on identity and sense of self. There were challenges in adults receiving adequate service with poor post-diagnostic support and ageist/ableist attitudes amongst professionals. Diagnosis was seen as both positive and negative which led to some finding difficulties in managing tasks of daily living and employment.</p>