Autistic people are at elevated risk of mental health conditions and experience significant barriers to effective support. While adaptations to therapy for autistic people have been proposed by clinicians, there is limited research on how helpful autistic people themselves rate these. We aimed to address this gap. Participants were 130 autistic adults aged 18 to 64 years (85.4% female) who completed an online survey of the helpfulness of 55 therapy adaptations. Overall, we found positive ratings of helpfulness for approximately half of the adaptations. However, significant variability was found at an individual level with most adaptations rated from not helpful through to extremely helpful. Neurodiversity-affirming adaptations were rated highest overall. Participants shared additional adaptations including general good practice, financial, modality, neurodiversity-affirming practices, practical, sensory/environmental, structure, and therapy style/techniques. Findings highlight similarities and differences between clinician and autistic people's perspectives, underscoring the need to include autistic people. Limitations of the restricted sample and generalizability are acknowledged. Future research including more diverse samples would be of value to expand on this research. The need to understand general preferences of autistic people and to individualize to the specific client is underscored by findings to begin bridging the mental health support gap for autistic people.